The GLS350d and GLS450 have different turbocharged V6 engines (powered by diesel fuel and gasoline, respectively), but are otherwise similarly equipped with 19-inch alloy wheels, a self-leveling air suspension, power-folding auto-dimming side mirrors, automatic headlights, LED running lights and taillights, a sunroof, automatic wipers, roof rails, rear privacy glass, a power liftgate and mbrace Connect remote vehicle access (via smartphone app; includes remote start).
Every GLS-Class model comes with all-wheel drive and a multimode terrain selector on the center console.
Interior highlights include "MB-Tex" premium vinyl upholstery, heated front seats, a 10-way power driver seat (with four-way power lumbar), driver memory settings, a power-adjustable leather-wrapped steering wheel, an auto-dimming rearview mirror, genuine wood trim and dual-zone automatic climate control. Electronics highlights include the COMAND infotainment interface (with both a control knob and a touchpad), an 8-inch central display, a rearview camera, Bluetooth, a 115-volt household-style power outlet and a sound system that features HD radio and dual USB ports.
The Premium package for these two models adds keyless entry and ignition, a power front passenger seat with memory settings, lighted door sills and multicolor ambient lighting, a navigation system with real-time traffic, voice controls, Apple CarPlay and satellite radio, as well as a couple of notable safety features (see Safety section, below).
The Lighting package bundles adaptive LED headlights and automatic high beams. The Parking Assist package adds front and rear parking sensors, an automated parallel-parking system and a surround-view camera system. Also available are three-zone automatic climate control, ventilated front seats, leather upholstery, a 13-speakerHarman Kardon sound system with a CD/DVD player, an SD card reader and "multicontour" front seats that add a massaging feature and adjustable side bolsters and shoulder supports.
The GLS550 starts with all of the above as standard, adding or substituting a V8 engine, 21-inch alloy wheels, adaptive suspension dampers, sporty exterior styling cues, soft-close doors and upgraded interior trim (including wood steering-wheel inserts). The optional Night package throws in 21-inch black wheels and gloss-black exterior accents.
Optional items on all three of the above models (GLS350d, GLS450, GLS550) include a panoramic sunroof, heated second-row seats, "designo" diamond-quilted leather upholstery and the Driver Assistance package, which consists of adaptive cruise control and several advanced safety technologies (see Safety section, below). The GLS450 and GLS550 can also be equipped with an Off-Road package that includes an upgraded multimode terrain selector, a dual-range transfer case and front underbody protection; on the GLS450, it also adds the GLS550's standard adaptive dampers.
The high-performance AMG GLS 63 starts with most of the above, adding or substituting an even more powerful V8, a sport exhaust, exclusive 21-inch alloy wheels, a sport-tuned suspension, upgraded brakes, adaptive stabilizer bars (the "Active Curve System" in Mercedes-speak), AMG-specific styling elements inside and out, enhanced bolstering for the front seats, upgraded leather upholstery (with a complimentary headliner) and a flat-bottomed sport steering wheel.
All four GL models can also be outfitted with a trailer hitch, a heated steering wheel, power-sliding second-row seats for third-row access, rear side window sunshades, a rear entertainment system, a WiFi hotspot and a 14-speaker Bang & Olufsen audio system.
The 2017 Mercedes-Benz GLS350d is powered by a 3.0-liter turbocharged diesel V6 engine that generates 255 horsepower and 455 pound-feet of torque. The GLS450 uses up to a 3.0-liter turbocharged gasoline V6 rated at 362 hp and 369 lb-ft of torque. The GLS550 gets a 4.6-liter V8 that churns out 449 hp and 516 lb-ft of torque. All three of these models come standard with all-wheel drive and a nine-speed automatic transmission.
The GLS550 pictured here comes standard with a turbocharged V8 engine that serves up sports-carlike acceleration.
The AMG GLS 63, meanwhile, employs a 5.5-liter V8 that provides an astonishing 577 hp and 561 lb-ft of torque. It comes with all-wheel drive and a seven-speed automatic.
According to the EPA, the GLS450 should return 19 mpg combined (17 city/22 highway), with the GLS550 dropping to 16 mpg combined (14/18) and the AMG GLS 63 bringing up the rear at 14 mpg combined (13/17). The GLS350d has not been rated as of this writing, but should deliver even better numbers than the GLS450.
Properly equipped, all GLS-Class models can tow a maximum of 7,500 pounds.
