unless u are circuit racing or really up there in the red line area its not worth it. you can spend the money your gonna spend on a pc3usb and custom tune somewhere else. you would also save alot buyin just the slip on. actually have a buddy wit a 954 w/ micron full system and me wit a yoshi slip on and he says he regrets spendin the money on the pipe and custom tune/pc3 cuz it wasnt worth the difference in the horsepower gain(he loves goin to the raceways here in texas). imo put the money else where like wave rotors, clip ons, paint, chrome, etc.