If it's the 6 speed Evo2 (99+ model) will need the chamber hacking off the side of the exhaust and a plate welding over it Some say you need to change the snorkels on the airbox lid to bigger ones and then up the jetting from 100 or 110 to 120 for the main, and from 55 to 65 on the idle jets You also get different sprocket's in the kit but they aren't needed, and I found 13:38 to be the best setup for when you come to replace them. If it's an older 7 speed bike then it should just be the exhaust that needs doing. hope that helps Danny