Despite the new name, the GLS isn’t, strictly speaking, a new car.
Instead, it’s a facelift of the Mercedes GL-Class that’s been around since 2012. The oily bits have largely been left alone, apart from the adoption of a new nine-speed automatic gearbox for the 3.0-litre V6 diesel, which makes up the vast majority of sales.
Although the engine still produces the same 255bhp, the extra ratios mean economy and emissions are improved. It’s also fairly brisk considering the 2.5-tonne heft of the GLS, with 0-62mph taking a respectable 7.8sec – a small improvement on the outgoing GL-Class.
If you want to go faster, you can still get an AMG variant with a twin-turbo 5.5-litre V8 producing 577bhp and peak twist of 560lb ft propelling the big SUV to 62mph in 4.6 sec and on to an electronically limited 155mph. If you opt for the AMG Driver’s pack this top speed can be increased to 168mph.
The rest of the changes are cosmetic or simply make the GLS even more lavishly equipped than the GL-Class. Up front is a new nose that mirrors the rest of the Mercedes-Benz range, while the rear gets redesigned exhaust tailpipes. Inside there is a new steering wheel and instrument panel and a redesigned centre console.
Three trims are available – AMG Line, designo Line and the AMG breathed on GLS 63. The entry-level model gets 21in alloy wheels, adaptive air suspension and LED headlights, a panoramic sunroof, a sports braking system and an aggressive AMG bodykit on the outside, while inside there is a 360-degree camera, tri-zone climate control, heated seats all round, a Harman and Kardon sound system, and Mercedes-Benz’s 8.0in infotainment system with DAB radio and Bluetooth connectivity.
Upgrade to the more luxury appointed designo Line and your GLS gains Mercedes’ active curve system, limiting body roll and increasing agility and safety. There is also ventilated and massaging front seats, four-zone climate control, temperature-controlled cupholders, rear sunblinds and a luxury quilted leather upholstery.
Looking for more speed in your life then the GLS 63 may very well be the answer with its aggressive bodykit, high-performance braking and exhaust system and AMG-embossed sports seats to go alongside the 5.5-litre V8 at the front. In this test we sampled the mid-range model with the default diesel motor on UK roads.