results are in on the HFM slip on for the 660 grizz the pipe is AWESOME. out riding with 4 friends and all of them said the sound of the pipe on that machine was perfect.
this pipe was just mean sounding. power differents crazy felt like total new machine it would wheelie in hi 4 wheel drive.
1st started in my garage i thought the pipe was kind of loud. but after full day test ride just sounded like it was made for that machine. never heard a big gun so not sure how they compare.
BUT THIS PIPE ROCKS. send your e-mail to this address and i will e-mail you the dyno sheet.

busawon@webtv.net

 

oops hfm. and at 189.00 thats good price.