The TS 91 I had originally installed in mine had a very small muffler for the size. In fact, I learned that it is the same size as the 61. Of course, the guy that is buying that setup is using a tuned pipe, and that's the right way to make it talk!

The 1.20 should be awesome!
Glad to hear about the control arms...Can you do a pic of the elevator/rudder setup?