Hi, I was wondering, what kind of hp/tq difference would AFR heads make over ported stock heads that have different valves as well. All the mods are a .600" lift cam, unsure of duration, FAST 90/90, stock ported heads, LT's, O/R y-pipe, spintech catback with cut-out, and SLP lid? I know, it would help to have the duration, but my friend is unsure on it. As is right now, the car lays down 430hp/395tq on a dynojet. OH, and if it matters, it's an M6.