i used the cpi single and can this year....main jets, 500; and i shimmed the needle in the mid-range by .030, (one of the shim kits will fix you up), the cpi pipe consistently would out accelerate and out climb the stock pipe with the rest of the sleds being in the same state of preparation....you need a little more air, i used two flo-rites in the back of the air box, but others have added air in other ways....on the dyno the power went from 149 stock to 151 with the airbox opened up and to 163 with the pipe and can.....venting the engine bay is a definite asset.....clutching and gearing changes also helped immensely.....most people that don't advocate after market pipes don't have the dynos to check what really works, and don't want to gamble 500 bucks on it, and i don't blame them....if you ride in noise sensitive areas, the can thing is something to consider.....it's not a problem where i ride and the weight loss of pipe and can was 15.5 lbs, the noise level is only slightly higher that stock, and mine is different from almost anyone elses', not to mention faster
