Japan's Best Car website has released info on the 2021 WRX. They say it's gonna have a 266 HP Turbo 1.8 liter flat four for the WRX, at least in Japan. The STI's gonna get a 315 horsepower 2 liter that's been in the WRX. That doesn't sound like much of a bump, but apparently torque is being boosted to 325 LB-FT, so that's a decent amount. I guess your better of buying the S209 that's available now. However, Earlier reports from Road and Track have stated that it will get the Ascent's 2.4 liter flat four that already makes around 260 hp. However, supposedly it could produce 330 hp plus. If they hook it up with the hybrid system that Subaru is developing now, it could produce even more power. It's expected to debut in concept form in October in Tokyo, of course.
Full Disclosure: All of this comes from https://www.torquenews.com/1084/more-next-generation-2021-subaru-wrx-sti-details-surface, where they are saying all this. Correct me if I'm wrong.
Subaru WRX STI specs
|Car type||4-door saloon|
|Engine type||Turbo Boxer-4, DOHC, 16v|
|Displacement||2.5 l (153 ci)|
|Power||309 ps (305 bhp / 227 kw) @ 6000 rpm|
|Torque||393 Nm (290 lb-ft) @ 4000 rpm|
|Power / liter||124 ps (122 hp)|
|Power / weight||200 ps (197 bhp) / t|
|Torque / weight||254 Nm (188 lb-ft) / t|
|Layout||front engine, all wheel drive|