providing/obtaining dyno charts for the simple bolt ons would be the best way to determine which setup would provide the most HP gains. yes i admit it, i used to drive a honda. i never dynod the SOB but with the 3 major bolt ons (intake, headers, exhaust) id estimate that i obtained a mere 10-15 hp. but anyways, why would you wanna race an x? for shits and giggles i guess.