yeah, i did the PI intake in nov 06, PI cams in dec 06, and PI heads in sept. 07. if you can, do for the full PI swap. you will love the throttle response that heads give, and the top end pull is so much better than the NPI. i dont have dyno sheets yet, but once i get the magnaflow catback again i will be throwing her on the dyno. stock tune with all my mods, i dynoed at 218rwhp and 284rwtq.