I'm torn. I just picked up my 07 YZ 450F. It came with the GYTR Quiet Muffler and the GYTR stainless head pipe w/resonant design. The bike belonged to the owner of the dealer and he put lots of aftermarket stuff on to show off the products. The pipe sounds and performs great, but is rated for closed course only, with no spark arrester. I am going to convert my YZ for the woods and need to have a forest service approved pipe. Should I try to fabricate a screen for the GYTR and hope that I can humor the green suited dudes, or should I just sell the GYTR and get a rated system on the bike? I was thinking about the FMF Q pipe. Anyone have any recommendations?