Pretty hard to find after market for those sleds and I really doubt you will. I've seen people just take off the muffler and put a pipe. Louder, but the bigger thing was weight. That muffler on there weighs about 12-15 lbs. Yeah, heavy for a box. Saw one guy with a 583 put a muffler from a 4 wheeler in there. It stayed quiet and it saved him about 7-8 lbs.