If you can weld, , what I did with mine was bought some conical pieces that went from 1 1/2 to 2 inches, cut them down, and welded them in between the factory pipe and a short piece of 1 3/4 inch pipe. Then I just slipped the (admittedly different from the Commando) mufflers onto the 1 3/4 pipe section. It was more complicated than the slip on reducers, but it looks way better and will never leak.