The base 2021 Mercedes GLS450 comes equipped with a 3.0-liter twin-turbo V-6 that produces 362 hp and 369 lb-ft of torque and comes with an EPA-rating of 16/22 mpg city/highway. The next step up is the GLS550 that is powered by a 4.7-liter twin-turbo V-8 that churns out 449 hp and 516 lb-ft of torque and delivers 14/19 mpg. The range-topping AMG GLS63 packs a 577-hp, 561 lb-ft of torque twin-turbo 5.5-liter V-8 that comes rated at 13/18 mpg. 4Matic all-wheel drive is standard across the board and a nine-speed automatic backs the non-AMG models while a seven-speed automatic backs the AMG GLS63. With the third and second rows folded down, the GLS offers an impressive 93.8 cubic feet of cargo space.
Standard features in the GLS450 include Airmatic air suspension, Dynamic Select drive modes, power-folding third-row, remote start, power folding mirrors with Mercedes-Benz logo projector, 19-inch wheels, Nappa leather steering wheel, LED interior lighting, heated front seats, power moonroof, and a power liftgate. Available features include the Active Curve system (active stabilizer bars), an enhanced off-road driving program (adjustable off-road modes), 21-inch AMG wheels, interior aluminum trim, heated and cooled front cupholders, cabin-air purification system, heated second row seats, Nappa leather upholstery, 8.0-inch display with Apple CarPlay/Android Auto, a rear seat entertained system, and a Bang & Olufsen BeoSound premium sound system. The AMG GLS63 comes with many of the above features as standard but adds AMG Sport Suspension with adaptive damping plus, an AMG high-performance braking system, an AMG Sport exhaust, and available 22-inch AMG multispoke wheels.
The GLS-Class comes standard with Active Brake Assist (collision warning and automatic braking), Attention Assist (drowsy driver warning), Trailer Stability Assist, Crosswind Assist, Pre-Safe (accident preparation system), and a rearview camera. Opt for the Driver Assistance package and your GLS will get Lane Keeping Assist, Speed Limit Assist, Pre-Safe Plus, adaptive cruise control with Steering Pilot, Active Blind Spot Assist, and Active Brake Assist with Cross-Traffic function (automatic braking for cross traffic and pedestrians). The AMG GLS63 comes standard with all the above features.