RE: Welcome to Club SAITO !
I have found also that Saito has changed the muffler size to smaller on the .72 ... At least on the curved exaust pipe - straight muffler version... I had to order a replacement muffler and the one they sent me is same size as the .56 muffler (smaller) but with a 12 mm threaded end instead of the 10 mm .56 threads... The OD and ID of the muffler are .56... Haven't gotten it back in a plane yet to see how it does...