The 2020 Mercedes-Benz GLS in Photos

It takes as much as 17 horsepower to run the hydraulics, aided by the 48-volt electrical architecture. The system uses a camera to scan the road about 450 feet ahead and preemptively adjusts before the wheels get to that spot. It won't come cheap, though, as it's an $8200 upgrade on the GLE.

The fact that almost no customers will do this kind of off-roading is not the point, according to Zygan, who declared, "We want the car to be more capable than the driver." Mercedes, true to its "the best or nothing" tagline, is banking on a halo effect for consumers because its SUVs possess this surplus capability.

More impressive, and far more relevant, is how well the suspension absorbed the dirt ruts surrounding the dune, erasing an impressive and immediately noticeable amount of body motion. It feels, we imagine, like royalty being paraded around on a litter: There's a sense and an appreciation that a lot of energy is being expended down there to make this smooth ride possible.

The active suspension also enables the funky bouncing feature shown above; its name, Free Driving Assist, is equally funky. It's there to help the GLS hump its way out of a moderate bind from a soft surface. It will most certainly be used more often to peacock at stoplights, a behavior which we admit to having tried (could this feature be any more Vegas appropriate?).

With its seriously large 21- and 22-inch tires (the 22s have a section width of 325 mm in the rear, and the available 23s are 340 mm wide) aired down to 17 psi, the GLS did indeed conquer Big Dune one drifty curlicue at a time, although there's nothing like sand to make it feel as though the GLS580 could use double the power of its 483-hp V-8.

Definitive conclusions at this point are few. The front seats are supremely comfortable; the second row has a lot more available space; the V-8 sings with a muted refinement; and they are never, ever going to get all the sand out of these prototype GLSs.