on a wrx a bov isnt needed until around over 16.5 psi. If you get it, your just gonna get noise...it wont really serve a purpose unless your really boostin. Ive got a 03 sedan wrx its got engine wise ....aem cai, gt spec v1 header, invidia bellmouth dp, blitz nur spec catback, and a blitz sbc-id @ 16.5 psi..have never had a problem with stock bov. Sorry just dont want any one wasting money. Your better off buying a boost controller first.