Those STIs are beasts! If I was your friend, I would look for a stock/unmolested one. If not modded properly, they are susceptible to problems such as ringland failure. If modded properly, you could make 400 awhp pretty easily and be safe. The trans is pretty bullet proof. The adjustable diff is awesome. Along with the suspension, brakes, seats, exhaust note, looks, BBS wheels, acceleration, AWD, and pretty much everything else.
Can't go wrong with one. I have a '11 WRX.