The changes from the regular Q8 to the SQ8 are very mild, at least from a styling standpoint. Much of the silver and stainless-steel finishes have been changed to black, which up front makes the SQ8 look more menacing. The main grille inserts are just black, without any brightwork. The rear bumper has the most obvious styling changes. The faux skid plate has been replaced by a faux diffuser, emphasizing the SUV's sporting pretensions. The rectangular exhaust outlets are replaced by a quartet of oval tips.
More subtle changes hint at the SQ8's improved performance. The SUV sits lower than the standard one, making it look sportier, and it's probably a result of sportier suspension tuning. We can also see very large brakes fitted, particularly up front. On the front calipers, we can make out Audi Sport logos on the calipers.
What we can't see is what's under the hood, but there is a hint on the outside. On the hatch is a TDI badge, indicating that this has a diesel engine. This is in line with Audi's performance SUV offerings in Europe which also feature diesel engines, such as the SQ5 and SQ7. We wouldn't be surprised if the SQ8 used the 429-horsepower turbodiesel V8 found in the SQ7.
If an SQ8 makes its way to the U.S., don't expect to see the diesel V8 offered. Instead, it would likely use a gas engine, perhaps an uprated version of the 335-horsepower V6 in the regular model. It could also use a detuned version of the gas V8 rumored for the also upcoming RS Q8. That engine, in turn, may come from the Lamborghini Urus. A detuned version of the RS engine would make some sense considering we saw a prototype that looked very much like this one with a reported V8 rumble. That reported rumble initially led us to think it was just a test vehicle for the RS Q8, but now appears it could simply be the "plain" S.
Considering the fact that this prototype was completely undisguised, we would expect to see the production model revealed by the end of the year.