Seany ... I used the stock muffler cause I cannot get a pitts style one here in Asia, sad huh? I did not rotate it but the cown was an easy fit, came out on the side at the bottom. I could only get 9,500 RPM on the 16x6 with 15% Cool Power. No Seagull Laser's here too. Oh well ... so tempted to get it on some 65" plane.