Ok, some people have been interested in an aftermarket exhaust for the GS 500 F. After speaking with 3 motorcycle repair/custom shops and hours of online searching, I have found that Vance & Hines makes one for the 99-02 models. We are trying to find out if this will fit the '04's. Maybe soon some of us will be able to get a little more from our 500's. There is also a jet kit for it too.