Top speed (according to my bike and trial) is 119 MPH. However, I also weighed 225 pounds at the time. With a 160 pound rider and a tail wind, top speed should be right at 128-132MPH. Kit won´t add much but a new jetting and exhaust will give you better power and faster acceleration to top speed. In addition, changing your gearing to a shorter tooth on rear with a jet kit will keep acceleration about the same but will improve top end 3 or 4 MPH.