You guys need to start fighting for your rights. The government can't force you to put a chevy muffler on your chevy truck, or ford muffler on your ford truck. You can go to any muffler shop you want for a new muffler. In some areas if you have too loud of exhaust on your truck you can get a ticket for noise, plain and simple.
For many older snowmobiles there is no replacement oem exhaust even available anymore, aftermarket or custom would be the only option, then what? If a muffler meets the 88db test that they do and it passes, then it is should pass. The brand shouldn't matter as long as it meets the db level criteria, whether the snowmobile is new or old.
Olav Aaen wrote an article about this years back. I need to do some digging and find it so you guys can get your snow clubs together to fight this. Sure there are loud aftermarket exhaust out there, but there is also plenty that pass the decibel level requirements as well. Just some food for thought people.