I am figuring 2% more horsepower maybe, and not worried aboutthat really. I am trying to make the thing run clean without killing my performance. it should get a better seal at the rings and not use a ton of oil yet have some vacuum from the intake. i suspect when i dyno my bike after its on it will shoe very slight HP gains but increasing  as RPMs increase. gimme a month....i will post waht i find in detai right here.