2002 Subaru Outback died, wanna engine swap

[Idrumbetter]

Hey all, I have a 2002 Subaru outback that blew the motor due to head gasket failure. I was wondering if a newer sti engine would fit inside and pair to the existing transmission (just had that get a new clutch and worked on) for at least a bit. If not then I'll get a sti transmission as well if it matches and fits. How much would it cost and take to get it in? I want to make it a low 12 second outback. I want to swap it because it sounds fun and would make me different than most everyone in my area. The sleeper aesthetic is what I am going for. It is a 5 speed manual transmission right now.

 

[Idrumbetter]

Or is there another route other than the sti to get to "400" hp theoretically needed for 12 seconds? I would be okay with 350 though. I know I will probably need forged internals