It's hard to wrap your head around the physics of a vehicle the size of a small office park carrying around enough power to nearly keep pace with supercars. Yet, that's precisely what the GLS63 is. Does a vehicle like the GLS63 make sense? Well, yes and no, but after taking a quick spin in one, I can assure you that no matter your opinion on its provenance, it's hard not to smile while driving at full tilt.
Whether it leaves you unsurprised or horrified to learn this, SUVs now comprise a majority of Mercedes-Benz sales, and approximately 50% of all AMGs. Combine that with AMG's desire to shove its handcrafted V8s into as much metal as possible, and the GLS63 is basically an inevitability, but the latest version is pretty bonkers even by its own standards.
The first-gen GLS63 (née GL63) landed at the LA Auto Show in 2013 with a 5.5-liter, twin-turbocharged V8 pumping out 550 horsepower and 561 pound-feet of torque. The new sheriff in town practically embarrasses its forebear, thanks in part to a 4.0-liter, twin-turbo V8 that pushes the output to a more stratospheric 603 hp and 627 lb-ft.
But that's not all! For the first time, Mercedes-AMG also adds the 48-volt mild hybrid setup from its 53 line. EQ-Boost, as it's called, slaps an electric motor between the engine and nine-speed automatic transmission that can add an extra 21 hp and 184 lb-ft.
You can't just add those numbers together, because EQ-Boost is more about filling in torque gaps and extending stop-start capability. It works seamlessly, providing little hint that there's anything beyond a V8 providing motive force. And speaking of that eight-pot, it remains every bit the gem it's always been in the new GLS63, with a slight hint of turbo noise accompanying a physics-professor-confounding amount of forward motion. From a stop, it's hard not to break out in a cackle as this 5,700-ish-pound behemoth uses every inch of grip that can be afforded from its 23-inch Michelin Pilot Sport 4S summer tires.
It's hard to overlook the GLS63's massive wheels, and not just because they almost come up to my hip. AMG's historic Monoblock design is back in action as an option for GLS63 buyers, and I am in love with them. They fill out the wheel wells nearly perfectly, giving this three-row ute a surprisingly sinister look, especially in conjunction with all the other little AMG-specific nip-tucks, which include angrier bumpers and the trademark quad tailpipes.
There's one big downside to these wheels, though: ride quality. The wheels' collective heft is evident when driving on any pavement that isn't perfectly smooth, transferring more noise and motion to the cabin than I'd prefer. Every other facet of the GLS63's ride quality is stellar, though. The adaptive air suspension is buttery smooth in Comfort mode, and some clever electric motors and gears in the active anti-roll bars can reduce unwanted lateral motion.
That's in Comfort mode, though. Throw the GLS63 into Sport or Sport Plus mode, and things start to get weird. I didn't think the GLS63 could emulate a sports car that well, but my concerns are immediately put to rest with a flip of the drive-mode switch. The suspension firms up, the exhaust gets louder and the throttle gets much more sensitive. I am actually genuinely impressed at how sorted the GLS63 feels as it's chucked into a corner, seemingly ignoring its immense momentum and sticking between the lines -- an admittedly tough thing to do at any speed, considering how freakin' huge this SUV is.
The only thing that feels like it needs improvement is the GLS63's brakes. At lower speeds, the pedal is easy to modulate and stops arrive smoothly every time. At full clip, the car feels under-braked, although some of that is likely down to the constant paranoia of how many pounds need to be brought down before each corner. I wouldn't say Mercedes-AMG needs to add some carbon-ceramic stoppers in this situation, but maybe some slightly more aggressive pads would add a little extra peace of mind for the five owners who do decide to chuck the GLS63 about.
Even though it's got performance chops, the GLS63 remains a full-on luxury vehicle, and it has the interior to match. On my well-optioned tester, very soft leather exists on just about every surface. The general design is pretty much the same as what you'll find on other new M-B SUVs like the GLE-Class, and it works -- the dashboard has just enough interesting contours, and the grab handles on either side of the infotainment touchpad lend some off-road cred (at least in the visual sense). I'd do everything in my power to skip the carbon fiber interior trim, though -- it looks way too garish on the GLS, which is better suited to something a little fancier, like one of Mercedes' many matte-finish wood finishers.
Space abounds in the GLS in both the first and second row, while the third row is more than enough for the occasional kids or small adults on short trips. Otherwise, fold those extraneous seats into the floor and exchange 'em for more cargo space than you'll know what to do with.
The tech in the 2021 Mercedes-AMG GLS63 certainly befits its $132,000 starting price. In addition to all the whiz-bang stuff like electronic sway bars and adaptive air suspension, the GLS63 sports a bevy of standard safety systems, including automatic emergency braking and lane-keep assist. The latter is a little heavy-handed, and it can start acting strange when the width of the car begins to match the width of the lane, but generally it's smooth and unobtrusive.
Finally, there's MBUX. Mercedes-Benz's latest and greatest infotainment system resides on the centermost of the two 12.3-inch screens gracing the dashboard. As I've said in just about every Mercedes-Benz review written in the last year, MBUX is great. It eliminates many of the complicated sub-menu browsing required in the old COMAND interface, and it minimizes distraction by giving the driver three different methods of manipulating the information on screen (steering wheel thumbpads, the handwriting recognition pad on the center console or just touching the screen itself). There's nothing in here unique to the GLS63: The screens have some AMG-specific displays, but otherwise it's exactly the same getup I see in every other modern Benz. Yes, Apple CarPlay and Android Auto are both included.
It's hard to walk away from the GLS63 anything less than impressed. It's just as comfortable as I want a Mercedes to be, yet a simple switch can flip everything on its head and give the vehicle almost preternatural agility. It's big and silly and probably doesn't need to exist, but after driving it, I'm happy it does.
Editors' note: Travel costs related to this story were covered by the manufacturer, which is common in the auto industry. The judgments and opinions of Roadshow's staff are our own and we do not accept paid editorial content.