Review: 2021 Mercedes-Benz GLS 63 AMG 4MATIC+

It was inevitable for Mercedes-Benz to stuff their largest SUV with the largest & most powerful engine they produce at the moment. At $168,000 CAD, the 2021 Mercedes-Benz GLS 63 AMG 4MATIC+ is the ultimate in Mercedes-AMG luxury.

2021 Mercedes-Benz GLS 63 AMG


Engine – The handcrafted 4.0L twin-turbocharged V8 produces 603 hp and 627 lb-ft of torque (450 kW & 850 Nm). In an SUV that tips the scales at almost 2,700 kg (5,952 lbs), it can accelerate the GLS 63 AMG to 100 km/h in 4.2 seconds, according to Mercedes-Benz. From behind the steering wheel, it doesn’t feel that quick. Let me explain.

You do feel the acceleration pushing you into the seats but because you sit so high off the ground, the sensation of speed isn’t the same as in a sports car – or even a smaller SUV. So your brain thinks that you’re not really going that fast but when you look at the speed in the head-up display, you see that you’re actually already way beyond the speed limit and flashing red & blue lights behind you. The GLS 63 has a very strange sensation of speed.

2021 Mercedes-Benz GLS 63 AMG

As for fuel economy, do you really care? Officially it’s rated for 12.9 L/100km (18.2 MPG) on a highway and 16.3 L/100km (14.4 MPG) in a city. The highway fuel economy is sort of achievable thanks to the EQ Boost system. It is a 48-Volt mild hybrid setup that aids the engine with fuel economy and quick bursts of acceleration. The GLS 63 also has cylinder deactivation which suits off half of the engine’s cylinders under light throttle applications, such as cruising down a highway. 

Transmission – In Comfort mode, the 9-speed automatic is unnoticeable, which is a good thing. The shifts are pretty much imperceivable but still quick. In Sport and Sport+ modes, the shifts are faster still with quicker response times to your inputs. But the shifts are more ferocious to make you feel as though you’re in a very sporty SUV.

2021 Mercedes-Benz GLS 63 AMG

Braking – Hidden behind the 23” monoblock wheels are red 6-piston front calipers and single piston rear calipers. Despite the heft from the enormous body, the brakes feel effortless when it comes to stopping the big beast in everyday traffic. Under more enthusiastic driving conditions, it takes a bit more effort from your right foot against the brake pedal to bring the 2.7 tonne SUV to a stop. 

Handling – The 2021 Mercedes GLS 63 AMG comes standard with air suspension and adaptive dampers with three different stiffness settings. There is a noticeable difference between the different settings but even a company as rich and powerful as Mercedes-Benz cannot bend the laws of physics. At 2.7 tons, the GLS 63 still has a noticeable amount of body roll even in the Sport+ drive mode with the stiffest suspension setting. Don’t get me wrong, it’s still quick and it has quite a bit of grip from the 285 wide front tires and 325 wide rear tires but the weight makes the SUV feel like you’re trying to navigate a cruise ship.

Off the beaten path, you probably won’t want to take the GLS there. It does have a Trail and Sand mode for better traction but with high performance summer tires, I can’t see it performing very well in sand & snow. 

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2021 Mercedes-Benz GLS 63 AMG Interior


Ride Comfort – The 2021 Mercedes-Benz GLS 63 AMG does a great job of being a comfortable SUV but it could be slightly better. The 23-inch monoblock wheels are wrapped with low profile tires which look really good. But you can feel sharp bumps being translated into the cabin. For a little bit more comfort, you can opt for the standard 22-inch wheels or go down to the GLS 580 with 21-inch wheels. That one also has the same air suspension system.

But for an AMG vehicle, the ride is really good without feeling floaty. However, the SUV can make you have that floaty feeling when you turn on the massaging front seats. Not only that, they also provide excellent support for long commutes. The 2nd row captain’s chairs (bench seating is standard) can also have a massaging and ventilating feature if you opt for the Premium Rear Seating package.

2021 Mercedes-Benz GLS 63 AMG Interior

Interior Space – The front occupants have a generous amount of space and are treated to a lot of creature comforts. Headroom is plentiful as is legroom but at 6’4”, my knees are perilously close to the start/stop button. I can’t help but wonder that in the event of an accident, my knees are going to be smacking that protrusion if the knee airbags don’t deploy. However, when you’re not having an accident, the front seats are heated, ventilated, and massaging with multiple massage functions. 

The 2nd row captain’s chairs also offer plenty of space for taller adults like myself with no issues in terms of legroom. The chairs are also powered with pretty much the same amount of articulation as the front seats. And as mentioned earlier, you can option them with ventilation and massaging features.

2021 Mercedes-Benz GLS 63 AMG Interior

As for the 3rd row, adults can’t really fit back there unless the 2nd row seats are moved quite far forward. As well, getting into the back seats will test your patience. The passenger side 2nd row seat has a button that can move the seat forwards or backwards electronically to allow access to the 3rd row. But the seat movement takes a good 20 seconds to move. It may not seem like a long time but when you’re waiting in the pouring rain for the seat to move, it’ll feel like you’re waiting for 5 years. With the captain’s chairs, it’s faster to just pop by in between the seats.

Behind the seats, the 2021 Mercedes-Benz GLS 63 AMG offers 355 L (17.4 cu-ft) of cargo with all rows of seats up. With the 3rd row folded, it has 1,210 L (42.7 cu-ft) of cargo volume and with the 2nd row folded, it has 2,400 L (84.7 cu-ft) of cargo space. The 3rd and 2nd rows can be folded and raised electronically and there’s a button in the trunk for lowering the back of the GLS for easier loading or unloading.

Noise, Vibration, & Harshness – For a 6-figure SUV, you’d expect it to be blissfully quiet inside the cabin. And for the most part it is… until you put your foot down of course. With the SUV in Comfort mode, there are no rattles or squeaks from the trim pieces. The engine is well muted but you do hear a bit of noise from the tires at highway speeds. You can drown out that noise if you switch to Sport or Sport+ modes and open up the exhaust at which point the GLS 63 AMG sounds like a snarling monster. Crackles and pops from the exhaust are loud but not obnoxiously loud.

2021 Mercedes-Benz GLS 63 AMG

Odds and Ends

Gadgets – With a starting price of $160,900 CAD ($133,150 USD), the 2021 Mercedes-Benz GLS 63 AMG is actually $5,000 CAD ($8,150 USD) less expensive than the starting price of the BMW Alpina XB7 and a whopping $43,000 CAD ($46,350 USD) less expensive than the Range Rover SVAutobiography. So in a sense, the GLS is a bit of a bargain. However, this being a German vehicle, the options list is still enticing you for your money. A fully loaded GLS 63 AMG with all the options will cost $197,250 CAD ($158,960 USD). This particular demo vehicle had an as tested price of $167,700 CAD ($147,930 USD).

For your money you get the usual stuff like satellite navigation, panoramic sunroof, power liftgate, power driver & passenger seats with memory, heated & ventilated front seats, heated steering wheel, heated & cooled front cup holders, heated 2nd row seats, soft leather upholstery, a massive head-up display, a full suite of advanced safety & driver aids, and the aforementioned massaging front seats. Extras on the GLS include things like carbon ceramic brakes, a carbon fiber engine cover, a built-in dashcam, Burmester 3D surround sound system, rear seat entertainment system, carbon fiber interior trim, black exterior trim, the monoblock wheels, and the Premium 2nd row seating package with ventilating, & massaging seats.

2021 Mercedes-Benz GLS 63 AMG Interior

Interior Design – The interior is not that different from any of the other large Mercedes SUVs. The GLS does have genuine materials such as aluminum (or wood or carbon fiber if optioned) and it feels like a luxury vehicle. The only minor interior features that let it down are the indicator & gear selector stalks and the cover for the cup holders. Those pieces still feel like they’re off of a base A-class

Exterior Design – First thing’s first, the monoblock wheels are 23-inches in diameter and you can also get them in silver. The silver’s cost $1,500 CAD ($4,950 USD) and the matte blacks are $2,000 CAD ($5,450 USD). The rest of the GLS looks massive and much like a curvaceous box on wheels. There are no sharp edges but rather smooth corners. The AMG Panamericana grille is right in your face and along with the quad exhaust tips, that’s about the only major changes to the exterior styling when compared to the base GLS 450

Warranty – Just like every other Mercedes-Benz vehicle, the 2021 GLS 63S AMG comes with a 4 year / 80,000 km new vehicle warranty. It also comes with 4 years / unlimited km roadside assistance, 4 year / 80,000 km surface corrosion, and 8 year / 130,000 km warranty for certain emission parts. For more information on Canadian warranty, click here. For U.S.A. warranty information, click here

So is the 2021 Mercedes-Benz GLS 63 AMG worth your money? Well, do you really need a 600+ hp SUV? Probably not. Do you need one with 23-inch wheels? Probably not. Do you need one with a 300 km/h speedometer? Again, probably not. But we all want one. However, it is a lot of money but if you have that kind of money, it’s almost a bargain when compared to other ultra luxury SUVs. 

Thank you to Mercedes-Benz Canada for providing the vehicle.

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