Go for the Caddy and get a KY Majestic!!! Mine has an os46fx with the stock muffler, mounted at a 45 degree down angle so the muffler exits the bottom. Same radio setup as yours. Built to last and is nice and light. In my opinion the extra money for the kit is well worth it. I think using a pitts muffler would work fine with this plane. I fly off thick wetland grass and the stock wheels have held up well.