Mercedes-Benz's full-size, seven-passenger GL-Class SUV enters a new era when the first of the renamed GLS-Class vehicles are delivered. We know that German automakers like to adopt new naming conventions every time Mercury goes into retrograde, but why add an S? The "S" in "GLS" represents Mercedes' ambition for it to be the "S-Class of SUVs." The aim is to transfer the state-of-the-art experience of the S-Class into the GL-Class; the result features some inevitable compromises, but is ultimately successful in living up to the expectations that association builds as a showcase for high-end technology, safety, and luxury features.
Changes to the GL(S)-Class' exterior are subtle, but serve to bring the former GL-Class in line with the rest of the current Mercedes-Benz stable, with the most obvious revisions found right up front in the form of a new bumper, grille, and headlights. Making your way back along the GLS-Class, lines have been softened and rounded off slightly. Inside, the GLS-Class retains the GL's spacious seating throughout all three rows, while upping the ante with flourishes of luxury and new technology borrowed from the S-Class. New interior equipment includes a three-spoke multifunction steering wheel, instrument panel, center console, power driver seat (with memory settings), remote start, rearview camera, and upholstery design options. A 7-inch media display screen is standard; an 8-inch screen is optional with Mercedes-Benz's COMAND infotainment system, along with a TV tuner or the DVD player and rear seat screens found in so many SUVs today.
New features in the GLS-Class aren't limited to the seemingly superficial, however. Standard driver's assists in the GLS-Class include Collision Prevention Assist Plus, Crosswind Assist, Attention Assist, Mercedes' Pre-Safe System, Brake Assist, and the 4ETS electronic all-wheel-drive traction system. The Driver Assistance Package adds Pre-Safe brakes with pedestrian detection, Cross-Traffic Assist, Active Blind Spot Assist, and Active Lane Keeping Assist.
Like the GL, the GLS SUV will be offered in four models with different engines for each. The GLS 450 comes with a 362hp twin-turbo V-6, the GLS 550 has a twin-turbo V-8 good for 449 hp, the GLS 350d has a turbocharged V-6 diesel engine rated at 255 hp, and the GLS 63 AMG will pack 577 hp. Save for the AMG version, all GLS models will have shifting handled by Mercedes-Benz's 9G-Tronic nine-speed automatic transmission. "Dynamic Select" provides drivers with up to six transmission modes from which to choose, depending on optional packages. Comfort, Sport, and Slippery (for icy/snowy/rainy conditions) can be selected along with various settings meant to carry the GLS through light to demanding off-road driving. This means a lot of dials and knobs; you can have three separate dials on the center console alone, each of which requires a quick look down to operate. There are three more on the dashboard—and we haven't started talking about buttons. Maybe you'll get used to all of that in ownership, though. Or maybe it's just busy.
Inside, the GLS feels substantial and well built; it does live up to the "S-Class of SUVs" hype. For all of the influence of the S-Class to be found, the GLS-Class won't confuse anyone for its sister models from behind its steering wheel. Actually, the problem is found with the steering itself: It's easy (and true) to complain that modern electric steering racks don't have the feel of hydraulic ones, but that's not quite the issue in the GLS. For whatever lack of feel you can find to complain about in electric racks, they're no less likely to be precise than their hydraulic counterparts. The comically light steering in the GLS lacks that razor precision, delivering no sense of weight or feedback, which is especially important in big SUVs. A faster ratio might only get drivers in trouble in a vehicle this size, but the GLS would seem to represent a step too far in the other direction. On straight but narrow roads, it requires a lot of concentration and constant adjustment to keep in line; tight corners exaggerate the issue further.
For those who take a minimalist approach and search for the best match of engine to vehicle, the GLS 350d is the way to go. The diesel doesn't have the power of the V-8, but it has plenty of torque and offers good mileage. To return that kind of efficiency, the nine-speed transmission makes its way to ninth as soon as it possibly can. It relaxes the wallet come gas day, but on the road it feels like it has about two or three gears too many; the downshifts are constant and come any time you push on the gas. Being unable to dip into the swell of torque when you're trying to merge or accelerate a bit is annoying, though it does seem to be better when Dynamic Select is set to Sport mode.
The GLS 450's V-6 may not have the horsepower or torque of the V-8 (369 lb-ft to 516 lb-ft, to be exact), but it enters peak torque at 1,600 rpm versus 1,800 in the GLS 550. The V-8-equipped GLS 550 is a monster; power is available everywhere and is more than enough to blast onto freeways with confidence and overtake with ease. It's more than enough—for most, that is. If you feel like you'll just need more, the upcoming GLS 63 AMG will offer 577 hp, a seven-speed transmission rather than the nine-speed, and a 4.6-second 0-62-mph time—seriously fast for a seven-seater SUV.