I like DarZeelon's version of a PITA better, mmmmmm... I just purchased an ST G-90 for my Aeroworks Edge 540T but as the original poster stated, that muffler is so ugly. Also too big. I'd have to cut a lot of the cowling out the bottom just to fit it. So I was instructed by a few fellow RCU members to purchase the MACS bolt through 1 piece muffler. I am waiting for it to arrive from Tower but I am sure it will be a much nicer fit and look. Also the black finish will look awesome against the red and white bottom. I guess I am basing it on looks but I was also told that the muffler would be just as good, if not better than the stock muffler performance wise... Just my 2 cents... Happy Flying!!!