I drilled four 9/16 holes in my outer baffle and two 9/16 holes in the 2nd baffle which is about 12 inches from the first. I started with two holes then listened . Then continued on untill I was happy with the tone and volume. They sound much much deeper but only a little louder. I'm very happy with sound and the price was outstanding.FREE I figure if I did'nt like it I could always buy some slip-ons. Anyway no change in performance , but no other changes either same jets,airfilters ect... This is a brand new 07 SM only 1000 miles. Well if you just bought a new bike and can't quite afford new pipes try this while you save up, at least it does'nt sound like a saws-all anymore.
