That's my CAP and I've never owned a stock muffler for the 1.60 so I'm afraid I couldn't be much help with that but I can tell you that you can get a BCMA 42cc gasser for $295.00 that will fly the heck out of the plane a lot cheaper then that Surpass. I just ordered a Pro 52cc last night for a 30% plane for $475. Adam only charges $35.00 for overseas shipping too! I'm now flying mine on one of his 40cc gassers and it's awesome.