...how many engine mods do you want to make? How much tractibility and reliabliity do you want to give up? You wern't thinking of runnung pump gas were you? There is a lot more than just $ involved in figuring out your total "cost" to run that much hp...this is why I went with the 250 hp kit, as the nature of the powere delivery is of paramount importance to me, rather than the amount produced...also, I certainly expect to use pump gas and drive around like a stocker for extensive touring duty...a 350 hp monster that would terrify GR hisself whenever the motor is on, and all the compromises attendent to such a bike, are as far from what I want as a Rebel 250...