I have a 2002 scrambler 400 2x4 with the HSP pipe that comes with the 2 shims. I was wondering if anyone has 'experimented' with changing these and does it make a noticable difference in the powerband when going from no shims to 2 and vice versa.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Wow! That's from a galaxy far, far away. That was the first pipe I bought, and my memory isn't serving me well. Maybe give Jeremy and the folks at Hot Seat a call, they have lots of seat time and can tell you what to expect.