I recently put a supertrapp IDS2 and a dyno jet kit on my Wolverine. I used the 155 main jet and put 7 disc in the pipe and had a plug check done by by a atv mechanic. Runs smooth but just didn't help as much as i though it would. It definitly has better throttle response. I have a pro design filter system ordered, hope that will help some more

 

Pipes on fourstrokes are not that noticeable by the seat of the pants experience as two strokes but they do help.