Has anyone done this yet? I'm picking up a TMX that'll be change over to a vintage road racer instead of the scrambler style. I'd buy a GP but not many turn up and this TMX is only running me $100. I'm currently building a expansion chamber from the specs in the book. I kinda made a quick DIY thread in "How To" section on the forum. I'm just curious how many folks have attempted it here and what kind of results you got.