Mercedes-AMG's GLS63 Is A Ballistic School Bus

Mercedes has gotten quite good at this over the years and has recently identified a previously unfilled gap that apparently needed addressing: Buyers looking for a proper six- or seven-passenger SUV with 600 horsepower and a six-figure sticker price had nowhere to go until the 2021 Mercedes-AMG GLS63 showed up. When it arrives at dealers this summer, the AMG version of the GLS-class will claim the title of the world's most powerful three-row luxury SUV. In contrast, every GLS63 comes with a relatively spacious, power-folding third row that affords 17 cubic feet of rear cargo room behind it. As we learned from driving the AMG through the hills of Southern California, however, there's more to the performance of this hulking SUV than its power rating. The GLS63 is almost mechanically identical to the redesigned five-passenger GLE63 S SUV that we recently drove. With its two turbos huffing up to 18.9 psi of boost, this engine produces 603 horsepower at 6500 rpm and 627 lb-ft of torque at 2500 rpm. That's 26 more horsepower and 66 lb-ft more than the twin-turbo 5.5-liter V-8 that powered the previous-generation GLS63. Mercedes Unveils AMG63 Versions of GLS, GLE SUVs As in the GLE, the 4.0-liter features AMG's first V-8 application of Mercedes's 48-volt EQ Boost hybrid system, which sandwiches an electric motor-generator between the engine and the standard nine-speed automatic transmission.