We recently saw Mercedes reveal the 2020 GLS at the NY Auto Show. Two engines will be offered from the start — one of them is Mercedes' 3.0-liter turbo inline-six, and the other is a 4.0-liter twin-turbo V8. That V8 is reportedly good for 483 horsepower and 516 pound-feet of torque in the GLS. Now, the current 2019 GLS 63 uses the old 5.5-liter twin-turbo V8, but we expect Mercedes will downsize to the AMG 4.0-liter twin-turbo motor. That's the one Mercedes has been using with every new AMG 63 it comes out with, and they've been shaking more power out of that than the older, larger engine. Ultimately, that means this behemoth of an SUV will probably end up joining the 600 club, a not uncommon place to be nowadays.
Other obvious AMG touches include the blacked-out quad exhaust, beefy fenders and larger wheels and tires. Mercedes has taken the liberty of covering the headlights and taillights, so there could be some AMG-specific designs for those units, too.
Our spy shooter says he found the car in an AMG testing facility in Germany, but it looks like it hasn't been touched in a long while. We probably won't be seeing a reveal in the immediate future either, since the regular GLS isn't scheduled to go on sale until late this year. An on-sale date sometime in mid-2020 seems likely for the AMG version of the S Class of SUVs.