If the headers are intact I would reccomend that you shop around for Monster pipes. The slipons from a M900 should fit and they (the pipes) are easier to find. Leovince is good stuff, see if you can find a pair of those.
If your in the EU you will have a harder time finding pipes, due to regulations you have to run pipes that were made for your bike. The pipes are manufacured with a number that is bike specific... That reduces the list down to Staintune,GPR,Scorpion and a few other "unknown" brands... Hawk,Viper... cheap but quality is unknown...