if you're looking at a WRX (and not a STI) and you want to mod it then you should be careful of the tranny. I've heard some people mod their WRX and drive like sane people and haven't had too many problems. But I've heard from more people that have had to rebuild or replace their tranny after getting their WRX up near the 300hp mark (maybe they're dumping the clutch at every light).