Nothing is known about the first-ever SQ3 model, and there are three ways in which this can pan out.
The easiest and most obvious would be that it will use the same 2.0 TFSI powertrain as the S3 hatchback and sedan, complete with quattro and an S tronic auto gearbox. SEAT already has something similar in the MQB-based Ateca Cupra.
The latest reports from Germany suggest the next Golf R will go up in power from 310 to 326 HP, so there's a number for you! Another possibility would be that the 2.0-liter turbo engine would get some electric assistance.
It's widely believed that "35" models which AMG is working on will feature the EQ Boost system, so Audi wouldn't be out of line with a greener SQ3.
And finally, it's also possible (but not likely) that the S crossover will use a de-tuned 2.5 TFSI. Two things might push it down that route: Volkswagen's possible Tiguan R being powered by the 2.5-liter engine and the smaller SQ2 offering too much power from its 2.0-liter.
But if that were the case, we would see a provisional powertrain with the oval exhaust tips, not quads. Other than that, our secretive little prototype appears to have large air intakes with silver trim plastered over its front bumper. The performance breaking package (looks like it's from the Golf GTI) is complemented by large wheels.
Expect the SQ3 to come out in 2019, about a year after the regular version,