2018 Mercedes-Benz GLS

The Mercedes-Benz GLS-Class was introduced last year as a redesigned and renamed replacement for the GL-Class near the top of the brand's SUV lineup, and it returns unchanged this year save for the adoption of new naming conventions for some of Benz's active safety systems.

Technically, the G-Class is Mercedes's poshest SUV model thanks to its "baller" status among rap music stars professional athletes, but the larger GLS is the most practical thanks to its three rows of seating an a more modern and efficient interior design.

While the GLS is not as handsome as the Audi Q7 or Volvo XC90 against which it competes for attention from well-heeled family types, its boxy body makes its mass obvious. An upright rear end offers useful space for third-row passengers, even if that shape bears a stronger resemblance to a minivan's hindquarters than Mercedes would be willing to admit.

The range includes the GLS 450, GLS 550 and GLS 63. This is one of the few Benzes left where each model gets a distinct engine rather than multiple trims using motors tuned for various levels of performance.

At the bottom of the range, the GLS 450 gets a 3.0L turbo V6 that makes 362 hp and 369 lb-ft of torque. In the middle, the GLS 550 uses a 4.7L turbo V8 good for 449 hp and 516 lb-ft and the GLS 63 boasts a 5.5L turbo V8 cranking out 577 hp and 561 lb-ft.

All three engines come with Mercedes's 4Matic AWD system; the first two models have a nine-speed automatic transmission, while the GLS 63 uses a seven-speed with heavier duty internals to stand up to its beefier engine.

Conspicuous by its absence here is a diesel powertrain; you can blame Volkswagen's emissions faux pas of late 2015 for that. That's a shame, because a torque, efficient diesel is a perfect fit in a big utility like this. Fuel consumption ratings are 14.4/11.4 L/100 km (city/highway) in the GLS 450; 16.7/12.9 for the GLS 550 and 18.2/14.0 in the GLS 63.

Still, the GLS is a formidable machine that can tow up to 3,500 kg and handle a payload as heavy as 810 kg. All three models get air suspension, and each has brakes bigger than the last, the GLS 63 boasting dinner-plate sized front rotors measuring nearly 14 cm across. Standard wheels are 20-inchers on the GLS 450 and 21s on 550 and GLS 63.

The GLS 450's standard equipment includes power-folding side mirrors, active LED headlights, 20-inch wheels, keyless entry and start, heated steering wheel, navigation, artico upholstery, automatic climate control, 360-degree camera, collision prevention assist plus, blind spot assist and magic vision control.

GLS 550 trim includes a number of items optional in that lesser trim, like a panoramic sunroof, passive keyless entry, heated steering wheel and rear seats, massaging front seats, leather seating and automatic climate control. The intelligent drive package remains extra here, as does the towing package.

Predictably, AMG 63 trim gets AMG exterior styling, and its standard features largely echo those in the 550, adding a few active safety items that cost extra in lower-spec models. In fact, the 63 is equipped to the point that the only options are a few stand-alone items like a Bang & Olufsen stereo, rear-seat entertainment system, different wheels and a night package that trims certain exterior pieces in black.