can't answer that honestly, i took a big gun off and EHS custom built a 11.5:1 piston, custom web cam, oversized valve springs, port work, proto type Barker exhaust(mine and nasty700xx were the first 2 barkers ever made for the XX proto type for what is now available) new air box lid, controller and tuned it on a dyno. so i went from mild to wild. Tim Barker did the flow work on his flow bench and this bike is sick, should be a video soon of the hole shot I launched on sunday, smoked the 450's big time!thanks for the info how much of a difference did you notice after you got it on?