Just how much HP do you want and how much do you want to spend. You could upgrade to all of the following and most likely even more. Stage III heads 5 angle and ported.. 1mm oversize valves JWT cams MWS manifolds 3 " exhaust system Larger brakes all the way around (you'll need them) There's about $11,000 with no labor OH,, and you want to tweak your ecu for best HP (Nistune)