While we have seen the GLS undergoing winter testing before, it was never in such an advanced state of completion. This one look ready to cross rivers and do 1000-mile motorway trips.
It's still early to talk about styling, but even with all that camouflage we can tell the GLS II is less "look at me" and more "you already know I'm here." Much of the design will be shared with the smaller 5-seat GLE model, though they won't be identical twins. The only thing giving us reason to worry is the placement of the headlights, which is a little... Infiniti QX80.
Mercedes has pretty much revealed all the engines that will go into the GLS, most of which will be of the inline-6 variety. There's the diesel version that's already powering the S 350d and S 400d, plus the gasoline version with EQ-boost from the CLS 450 4Matic.
Though this has yet it be confirmed, it's likely that only a handful of version will be powered by a V8. One possibility is a GLS 560, featuring the same 4-liter as S 560. But an AMG version of the 600-hp variety is pretty much a certainty if you ask us. Rumors about a Maybach GLS model or two have been around for a very long time, and we don't see why Mercedes wouldn't stuff this vehicle with all its luxury know-how.
Source : https://www.autoevolution.com/news/2019-mercedes-gls-spied-undergoing-winter-testing-122749.html269