2021 Mercedes-AMG GLS 63

Two astronauts recently embarked into space on a Falcon 9 rocket, 1.7 million pounds of thrust propelling them on their 254-mile journey. While it may not be able to take you into orbit, the 2021 Mercedes-AMG GLS63 bears some similarity to the Falcon with how it gobbles up miles. Instead of nine Merlin engines, the AMG's thrust comes from a twin-turbocharged V8 engine shelling out 603 horsepower. This goliath of an engine can take the seven-passenger GLS63 from stationary to 60 mph in just 4.1 seconds while carrying seven seats, 26 speakers, and a built-in air fragrance system.

Formerly known as the GL, Mercedes calls the GLS the "S-Class of SUVs." Being the largest and most opulent model in the lineup, the GLS certainly fits the bill as a luxury flagship. We don't really see the need for a sporty seven-seat SUV but that hasn't stopped the AMG division from taking the docile GLS and transforming it into a heart-pounding thrill ride. With an all-new GLS acting as a base and no direct competitors save for the Alpina XB7, the new GLS63 could capture plenty of buyers who don't want to bump up to the next price level with options like the Rolls-Royce Cullinan. We spent a week with the 2021 GLS63 to evaluate how it performs as the flagship AMG SUV.

The old GLS wasn't much of a looker, but with the transition from blocky and angled designs to a more curvaceous language for Mercedes, the new GLS is vastly more attractive. It's an AMG, so it gets a Panamericana grille dominating the front end. The grille is huge, yet it doesn't feel disproportionate thanks to the GLS63's imposing size. The other AMG styling cues like a quad-exit exhaust system, a subtle roof spoiler, and rear diffuser are all present. Roof rails exacerbate the length of the machine, while a glass sunroof, LED lighting, and 21-inch wheels are also standard. Massive 23-inch wheels are also available to fill the massaged arches a little better.

The new GLS63 is larger than the outgoing model, as is fashionable in the motor industry. At 206.4 inches in length, it's 3.2 inches longer than before, while the wheelbase increases from 121.1 inches to 123.4. Width swells from 76.1 inches to 79.9 inches with the mirrors folded. Inclusive of the mirrors, the 2021 GLS63 measures 84.9 inches across. Height is lower though, dropping from 72.8 inches to 70.2. While at the time of testing curb weights had not yet been published by Mercedes-Ben USA, we suspect the chunky GLS63 to exceed the 5,699-pound figure of the GLS580.

No new colors have been announced for the 2021 GLS63, so we expect the options to be largely the same as those found on the non-AMG GLS. That car comes with regularly featured shades like Black and Polar White, as well as metallic finishes like Obsidian Black, designo Cardinal Red, designo Diamond White, Brilliant Blue, Lunar Blue, Selenite Grey, and Iridium Silver. Naturally, these colors will likely be included in the list of choices, but press photos have shown an attractive green too. We'll see what is on offer when the configurator goes live sometime later this year.

The new GLS63 is a notable vehicle for AMG, being the first from the sub-brand with Mercedes' EQ Boost starter-generator that adds 21 hp and 184 lb-ft of torque. This electric system helps with the start/stop functions, improves economy, and acts as a torque filler at low rpm, supplementing the gusto from the 4.0-liter twin-turbo V8 under the hood. On its own, the engine produces 603 hp and 627 lb-ft of torque. Along with a nine-speed automatic transmission and Merc's 4MATIC+ all-wheel-drive system, AMG claims that the GLS63 will accelerate from 0-60 mph in just 4.1 seconds. Top speed is electronically limited to 174 mph, but this is still the quickest three-row SUV in the world at the moment (until the BMW Alpina XB7 arrives). The hulking behemoth also features adaptive air suspension and active body control for better handling, stability, and comfort. While it does have off-road modes, no buyer is likely to ever take an AMG product trailblazing.

The GLS63 comes with a single powertrain option, a 4.0-liter twin-turbo V8 engine with 603 hp and 627 lb-ft of torque. This is supplemented by an electric starter-generator that adds 21 hp and 184 lb-ft to the equation. AMG's 4.0-liter bi-turbo V8 has always been a gem but this most recent application feels different. Other AMG cars shout like an attacking rottweiler but as a likely nod to the type of customer who drives a seven-seat SUV, the GLS63 is remarkably quiet. You can hear some violent snorts from the exhaust under hard acceleration and in Sport+ mode but the GLS63 has the most disappointingly quiet startup sequence we've experienced in an AMG. Buyers who value luxury over performance will cherish the GLS63's restraint but if we were opting for an AMG variant, we expect noise, and lots of it.

As with most AMG cars of this size, power from the V8 is sent out through a nine-speed automatic transmission to the AMG Performance 4MATIC+ all-wheel-drive system. The AMG nine-speed shifts smoothly under the vast majority of circumstances but can sometimes exhibit a rough downshift at low speeds. It's not a major complaint, though it is worth noting that BMW's eight-speed feels quicker and shifts with a tad more smoothness. The addition of a 48-volt mild-hybrid system helps to smooth out some of the kinks we've previously experienced with this drivetrain, including a stop/start system that is now near-seamless.

Even though it lacks launch control, Mercedes says the GLS63 can complete the sprint to 60 mph in just 4.1 seconds. This level of acceleration in a vehicle of this size feels like it should break all laws of physics, but such is the lunacy of the AMG division. Perhaps even more impressive than the straight-line acceleration is how the GLS63 fares when you toss it into a corner. Using the 48-volt mild-hybrid system, the AMG Active Ride Control virtually eliminates roll, keeping the seven-seat SUV unnaturally planted through the bends. The AMG-tuned 4MATIC+ system can send up to 100 percent of the engine's power to the rear wheels, helping to make the GLS63 feel far lighter than its hefty curb weight would imply. The steering feels surprisingly engaging for a vehicle of this size without being annoying during normal driving.

When you aren't pushing it hard, the GLS63's air suspension floats along silently, with very little road noise intruding into the well-insulated cabin. You can hear a low grumble from the V8 when it is pressed hard and torn up roads will shake the cabin a bit more than a non-AMG GLS, but you get the impression that AMG wanted the GLS63 to be tuned more for comfort than sport. If you do feel a hankering for speed, placing the car into Sport or Sport+ mode wakes up the drivetrain and turns the GLS63 from silent luxury car to aggressive back road missile. These modes change certain aspects of the engine, transmission, suspension, and exhaust, but these elements can also be altered individually if, for example, you'd like to pair a loud exhaust with Comfort mode suspension.

The GLS63 can almost be faulted for having too much customization but AMG smartly includes a drive mode selector on the steering wheel with easy access to Comfort, Sport, Sport+, and Individual modes. Trail and Sand modes can also be accessed, should they be required. As the most expensive GLS model, the GLS63 includes Mercedes' full suite of advanced driver assistance features which can essentially pilot the vehicle with limited attention from the driver. This is not a hands-free system but we did notice that the GLS63 could keep us in the lane with zero intervention for more than a full minute at a time.

The EPA has not yet published fuel economy ratings for the 2021 Mercedes-AMG GLS63, but the 2020 GLS 580, which uses a de-tuned version of the AMG's 4.0-liter V8 achieves 16/21/18 mpg city/highway/combined. But even with its mild-hybrid system and ability to shut down four cylinders, we averaged 12.1 mpg during a week of testing with virtually no highway driving, though it seemed like 20 mpg could be manageable with light throttle control and limited traffic. If you want the best fuel economy, it's best not to opt for the AMG model. The GLS63 is fitted with a 23.8-gallon gas tank, which would enable around a 287-mile range based on our observed fuel economy.

The interior of the latest GLS63 is a stunning place to be. The typically obsessive attention to detail and excellent build quality that Mercedes is renowned for is on full display here. The gorgeous leather seats are comfortable and feature heating as standard in the first two rows, with the third row optional. The front seats also feature ventilation and massaging as standard. In those two seats, the spacious feeling of the car is somehow enhanced by a pair of 12.3-inch screens that reside side by side. One is directly behind the steering wheel for driver info, while the second is touch-sensitive and handles infotainment with the aid of the new MBUX software. Heated and cooled cupholders and 64-color ambient lighting further add to the feeling of luxury and quality.

The GLS63 offers seating for up to seven passengers in its mission to bathe occupants with luxury and performance. A six-seater option is also available upon request, with captain's chairs replacing the second-row bench. Mercedes does not quote the dimensions of the third row but first and second-row passengers are treated to 39.4 and 40.2 inches of headroom and 40.3 inches and 41.9 inches of legroom respectively. Second-row occupants can slide and tilt their seats electronically and control the rest of the cabin electronics using a Samsung tablet mounted in the center armrest. Those same electric adjustments slowly fold the second-row seats forward, creating a sizable passthrough into the third-row. The rearmost accommodations aren't as spacious but still feature air vents, two cupholders, and four USB-C ports.

Sitting as the premier version of the flagship GLS, the GLS63 comes decadently equipped inside with expensive materials throughout the cabin. Nappa leather is included as the standard choice over the AMG-specific front seats with leather surfaces covering nearly all of the dashboard. An Alcantara headliner adds an even greater touch of opulence but we would skip the optional Alcantara-wrapped steering wheel. With no configurator yet available, it remains unclear which trim inlays will be available on the GLS63 but our particular example included carbon fiber. What few plastic surfaces there are on the interior are knurled and feel metallic to the touch.

The cavernous GLS is impressively capacious, but with the third row in place, there's only really enough room for a pair of medium suitcases and maybe some shopping bags. The 17.4-cubic foot volume measurement increases substantially if you flatten the third row and move the second row as far forward as possible. In this configuration, you have 48.7 cubes of volume, but all seats folded increase this even further, offering up 84.7 cubic feet of space.

In the cabin, you get cupholders in each row, along with generous center armrest storage, decent door pockets, and a reasonable glovebox. The center console also has a space for phones, keys, and wallets but we wish it was slightly larger.

The GLS63 is described as the S-Class of SUVs, and with a long list of standard features, it's not hard to see why. Forward collision alert with automatic emergency braking is standard, along with lane keep assist, an active driver condition monitor, blind spot monitoring, parking sensors, and a surround-view camera. The SUV also features dynamic LED headlights with auto high beams, 64-color configurable ambient lighting, heated and cooled front cupholders, dynamic LED headlights with automatic high beams, keyless entry and ignition, soft-close doors, and rain-sensing wipers. Other standard features include tri-zone automatic climate control and front seats that boast both heating and ventilation, as well as a massage function. The second row is heated as standard too, with this being an option for the third row. Ventilated seats are also optional for the second row, as is a head-up display for the driver.

The Mercedes-Benz User Experience (MBUX) is a massive improvement over the outgoing COMAND system in terms of usability but like BMW's iDrive system, it can be tricky for beginners. To make it easier to understand, Mercedes has included redundant controls in the form of a touchscreen, touchpad, steering wheel-mounted controller, and voice command. Drivers can, therefore, pick whichever control method feels most intuitive and stick with it.

Two 12.3-inch screens handle infotainment and gauge cluster duties with both offering a dizzying amount of customization. The gauge cluster, for example, offers multiple themes and the ability to configure the speedometer, tachometer, and center area. MBUX borders on being too customizable (if that can be considered a negative) but we suspect most owners will find one configuration and stick with it. If you prefer, Apple CarPlay and Android Auto are available but do not feature wireless capability. A Burmester Surround Sound System comes standard while a Burmester High-End 3D system is optional. A total of nine USB ports are dotted around the cabin and, of course, both navigation and Bluetooth connectivity are standard as well.

Thus far, the 2021 Mercedes-AMG GLS63 has had one minor recall, issued in February this year for interior switches that may not illuminate. But with this being prior to any deliveries taking place, all issues should have been rectified before the models ever hit the showroom.

Should anything go awry, a four-year warranty covers everything including the powertrain for the defined period of time or 50,000 miles, whichever comes first, but no complimentary scheduled maintenance is included although rivals like BMW and Audi do offer this.

Thus far, neither the IIHS nor the NHTSA has tested any version of the Mercedes GLS, but with a long list of standard and available features, we expect it to perform well.

As standard, the GLS63 features dynamic LED headlights with auto high beams, front and rear parking sensors, a surround-view camera, blind-spot monitoring, a drowsy driver alert, the PRE-SAFE and PRE-SAFE Sound collision preparation systems, and rain-sensing wipers. You also get frontal, side-impact, rear side-impact, and rollover curtain airbags. Also available is a head-up display to help keep your eyes on the road.

When a device reaches the ultimate level of opulence and luxury, car aficionados will often refer to it as the "S-Class" of its product category. So for Mercedes to call its own GLS the "S-Class of SUVs" without it being a hollow marketing exercise is pretty impressive. The GLS63 excels as a luxury vehicle, offering a nearly silent driving experience with sumptuous ride comfort. As an AMG, it manages to thrill drivers with shocking acceleration and road-holding that seem physically impossible for such a massive vehicle. As a luxury seven-seater then, we recommend the GLS63 as a top-notch option but purely as an AMG car, we have some minor gripes with it.

AMG cars are meant to be completely unhinged but the GLS63 feels more reserved than the rest of its brethren from Affalterbach. It's too quiet, too comfortable, and too livable for our liking, and we wish AMG would have been given a bit more license to make it stand out. These are more philosophical complaints than realistic ones though, as a 603-hp seven-seat SUV is outrageous no matter how you measure it. 99 percent of buyers will find more than enough to love with the non-AMG version of the GLS but for those one-percenters who want the best or nothing, the GLS63 is a near-perfect seven-seat luxury speed machine.

The 2021 Mercedes-AMG GLS63 AMG starts at a base price of $132,100 before a $995 destination charge. With a number of options and aesthetic upgrades available, it wouldn't be a surprise to pay over $150,000 for a fully loaded model. Our test model, for example, rang in with an as-tested price of $153,035.

The GLS63 is a standalone model in the range of Mercedes-AMG SUVs and tops the regular models sold under the Mercedes-Benz banner. Powered by a familiar 4.0-liter twin-turbo V8 engine with 603 hp and 627 lb-ft of torque that is supplemented by an EQ Boost starter-generator with an additional 21 hp and 184 lb-ft of torque, the GLS63 can get to an electronically limited top speed of 174 mph. Thanks in part to a nine-speed automatic gearbox and a 4MATIC+ all-wheel-drive system, the SUV hustles from 0-60 mph in just 4.1 seconds. Riding on 21-inch wheels as standard, the vehicle comes with a long list of features that includes heated first- and second-row seating, along with ventilated and massaging front seats. You also get a pair of 12.3-inch screens, one of which handles instrument cluster functions while the other controls infotainment to the Burmester sound system. Apple CarPlay, Android Auto, navigation, and SiriusXM satellite radio are all standard. Also standard is a configurable 64-color ambient lighting system, as well as heated and cooled front cupholders, nine USB ports, wireless charging, and parking sensors.

Until the configurator goes live, we don't know exactly what options will be available with the new GLS63 and what these options will cost. However, we do know that heated third-row seating will be available, as will heated and ventilated massaging second-row seats, an upgraded Burmester 3D surround-sound system, augmented reality navigation, an air fragrance system, and wheels as large as 23 inches in diameter. There will also be a seven-inch MBUX rear-seat infotainment system with a dedicated Samsung tablet screen as was equipped to our tester.

With only one trim level of the 2021 GLS63, buyers will simply have to select which options they'd like on their already well-equipped SUV. 23-inch wheels were the priciest option on our test car for $4,950 but the aggression they bring to the car is worth the price. We could easily do without the carbon fiber engine cover and Alcantara-wrapped steering wheel for $1,500 and $600 respectively but we would keep packages like the Burmester 3D Surround Sound System ($4,550), Warmth and Comfort Package ($1,100), and Executive Rear Seat Package ($3,700). For most buyers, the non-AMG GLS450 and GLS580 will be plenty fast and match the level of opulence found in the GLS63 for far less money.

The official purveyor of extremely fast, luxurious, and expensive BMWs is Alpina. The company has been tastefully and meticulously modifying BMWs for decades and has now turned its attention to the BMW X7, renaming it the XB7. The 4.4-liter twin-turbo V8 under the hood produces 612 hp and 590 lb-ft of torque, enough to get the hulking 6,000-pound SUV from 0-60 in four seconds dead, and on to a top speed of 188 mph. Inside, you'll find many of the same amenities as in the GLS63, including massaging seats and enough space for seven on stunning quilted leather. So luxury is certainly on par with that of the Merc, if not better, and it's faster too. However, the caveat is that the Alpina XB7 has a base asking price of $141,300, making it almost ten grand dearer than the GLS63. The benefit of the Alpina is that it's a less common and more detailed machine that is built in lower numbers. Still, choosing between these two is tricky and will likely come down to personal preference.

Audi's RS Q8 has been making waves in the international motoring community for its brilliance in design and performance, and with a base price of just $113,000, it's also a lot cheaper than the Mercedes-AMG GLS63. Powered by a 4.0-liter twin-turbo V8 with an eight-speed automatic, it produces 591 hp and 590 lb-ft of torque, a fair chunk less than the Merc. It also loses out in terms of passenger space, with just two rows of seating. This gives it a larger full-capacity cargo area but means that fewer people will be able to come along for the ride. The sloping roof also hinders rear headroom. Still, not that many buyers are likely to always use their performance SUV's people-carrying abilities to the full, and despite less power, the RS Q8 is quicker, getting to 62 mph in just 3.8 seconds. If you spec the optional ceramic brakes, the speed limiter is also raised to 190 mph. For speed and sportiness, the RS Q8 wins, but the GLS63 is far more practical and luxurious.