I am in the process of designing and building
a 321 SS tang muffler for my P-port RX8 engine.
I am using a $55 Mazdatrix RX8 flange.

Does anybody else want one as I am having the
SS water jet cut? It will look something
like this. If I don't hear from anybody
I am only going to make one and the price
will go up if you want one later.

If it turns out to be not quiet enough you should
be able to use a second Flow Master muffler under the
airplane to quiet it further. By that time the
energy in the exhaust should be far enough down
so the stock automotive muffler should live.
The RX8 engine is easier on mufflers to begin with.

I am not guaranteeing anything as the Wankel
always surprises :)

Paul Lamar