I rode all day Sunday with the PMB s/a and quiet insert. Just for reference, I have the '03 X440. It made the bike much quieter. I did see the area manager during the day but he didn't have his db meter so I'm still skunked on the sound measurments. As for power, I could feel the reduction. The insert made my X run like my C. Still fun just needed to use the clucth more. It was worth it to be able to ride in a "Kalifornia" OHV park.
I've been running the end cap for 4 months. The fit & finish is great and the ability to interchange the parts is great.
