I went to that Dacs? site??? Anyway there was an article about modifications to the exaust pipe. Sooooo I took it apart and cut off the baffel tube. They said you could drill holes in it or just cut it off. As I'm one never to do something half a** I cut the sucker clean off. Its an 80cc by the way. The thing is just mildly louder but has a little more of a throaty kind of sound(better)but as far as I can tell the HP did improve some . I'd say 1/2 to 1 HP if I had to guess. I don't expect it will be on the dino any time soon so you'll have to take my word for it........ Tom in W.V.