The Topstar 110 wasnt mine but I borrowed it from my flying buddy for a contest and flew her about 25 flights. It was fitted with a stock muffler but it really wasnt that noisy. A flying buddy has an Astral X 120 powered by YS 110 with Hatori #725 and its alot quieter than the stock muffler and as a plus you dont have to assemble and disassemble the pipe everytime you take off the wing. My opinion is that your better off with the Hatori than the long type pipes. Hope it helps.