I just picked up a super nice 07 S4R from the original owner to replace the 99 900S I had. The bike still has the factory exhaust on it so I am on the lookout for a good deal on a used system. My question is what all years/models will interchange with an 07 S4r? Thanks!!
if you get a mid pipe like this http://www.monsterparts.com/p/D-138B/Marving+Cat+Eliminator+Mid-pipe-+S2R+800-S4R.html (http://www.monsterparts.com/p/D-138B/Marving+Cat+Eliminator+Mid-pipe-+S2R+800-S4R.html) your options are plenty. you need to first figure out what you want, under tail, gp style or single side shotgun style.
It is a non issue now. I was researching the subject and ran across the Motocreations Boom tubes. How did that guy get in my head and make the exhaust I have envisioned for the last 5 years or so.
those are nice too