Besides welding brackets to suit, a good slip on the right size will work. many have used everything and some go with nothing down there. Blackie I believe has a hush thrush muffler attached to jardines. Sounds very good. (As good as a fast 3cyl. tractor gonna sound)
All in fun.
But seriously, what is driving the question? Cost? Sound? Desire for louder?
There is quite a lot to consider, to get good performance & achieve other goals.