Hi mate
Welcome to the club
Don't bother with an engine swap, yes, you will get more bhp, but what about brakes, suspension, arb's, gearbox?
If you buy a wrx, it will only cost £1k in mod's to get 340bhp. Or if you want more bhp go for the sti. A remap and exhaust will see 340bhp, or swap turbo, injectors and remap and 450bhp is quite easily achieved