I thought I seen where and I know you probably don't want any restriction but they have little inserts for the pipes to kind of calm them down just a little bit? Maybe something you could put in for the street and take out for the track? I know my headers go down into about a foot of pipe into Cherry Bomb switch you can see straight through and then kick out at the side. When I rev it up people like cringe and back off a little bit and go goddamn that's loud! :thumbsup:
