This peice available thorugh Yamaha, was the best noise suppressor, and exaust improvment I made to the stock exhaust. I cut out the spark arrestor, took out the stock noise suppressor, and installed this piece. It simply slides in and tighten one bolt. Thats it, my bike is improved in the noise dept., and is no slower than stock. In fact I think it has more low end punch when in the technical trails.