2021 Mercedes-AMG GLS63 Test Drive Review: A Seven-Seat Luxury Rocket
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.
2021 AMG GLS 63 Exterior
Dimensions
| Length | Wheelbase | Height | Max Width | Front Width | Rear Width | Curb Weight |
|---|---|---|---|---|---|---|
| 206.4 in | 123.4 in | 70.2 in | 79.9 in | 67.1 in | 67.9 in | 5,798.0 lbs |
2021 AMG GLS 63 Performance
Handling and Driving Impressions
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.
2021 AMG GLS 63 Interior
2021 AMG GLS 63 Trunk and Cargo Space
Warranty
| Basic | Drivetrain | Corrosion | Roadside Assistance |
|---|---|---|---|
| 4 Years / 50,000 Miles | 4 Years / 50,000 Miles | 4 Years / 50,000 Miles | 4 Years / 50,000 Miles |
Verdict: Is the 2021 Mercedes-AMG GLS 63 A Good SUV?
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.
2021 Mercedes-AMG GLS 63 Comparisons
2021 Mercedes-AMG GLS 63 vs BMW Alpina XB7
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.
2021 Mercedes-AMG GLS 63 vs Audi RS Q8
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.