not sure if this been posted yet, couldnt find anything in the search, but found this vid on youtube http://www.youtube.com/watch?v=LMnij-_4Zik

says rivets are drilled out and an aluminum tube has been slid down the pipe to cut out the baffle and allow the sound to only come out the rivet holes, has anyone here done this mod to there bike? also after doing this mod, will i have to rejet or anything?