Brad-A, I used a Saito 100 and the stock muffler. I had to cut away a fairly big hole, but it does not look too bad. Not sure what your muffler/engine setup entails, but I assume you cannot cut the cowl to fit. It I had to do it over, I probably would have purchased a Brisson muffler for the Saito, because it would have required less cutting of the cowl I believe. I may get another cowl from VF and try it sometime in the future. Not much help, but that is what I am doing. Ron[8D]