Accufab 70mm plenum/throttle body.

[blue00gt]

Changing to bigger intake and exhaust parts will only gain you power if they are a restriction. If you go too big, you will lose a ton of torque down low and maybe gain an inconsequential amount of hp on the top end. Without changing the plenum or adding forced induction I wouldn't go over stock or 70mm TB at most, and you won't see any gains with the 70mm without other mods.