had it for 1 week as of today. throttle response is up . It feels a little quicker up hills, but I don't have access to a dyno or track, so I don't know exactly how much more power it gave me. The overall sound is awesome!!!. I don't really care for the sound of the bypass valve- "chooooo", but the sound of the turbo spooling up is sweet. it sounds like a 737 when they punch it for takeoff.
if you get the hks bov, don't recirculate it. i understand that if you do, you have to take out the fin that makes the distinct whistle....people have told me it sounds like crap. just a heads up.