I have the DAX Hi Performance pipe and I am getting the same speed as my original pipe, the difference is I went from a 36 T sprocket to a 40 T sprocket. So in reality it increased about 2 to 3 miles an hour. Also with my original pipe I was having to slightly choke the bike in the lower speeds to get good acceleration and un choke after 25 to get up to 32, (this using 2 different carbs). With the new pipe it rolls right up to 32 with smooth and better acceleration. The clearance is close on the peddles, may have to do a little bending.