Marcus:
You are absolutely right, anything will work. You could in theory use the tubing from a vacuum cleaner for the exhaust system...don't laugh, it's been done. I like the Folgers idea besides, I've always enjoyed the smell of roasting coffee.
TravelGuy has already jumped through the engineering hoops, why not get a set of actual headers from him and go from there. Besides, didn't Hombre have a Super Trapp disk silencer on his R3? I thought I saw a picture of his when I was lurking over there one time. Like I said previously, the stock exhaust header on the R3 isn't really a header, it's a manifold made from thin wall stainless and fabricated to be aesthetically pleasing not efficient. About the only time you'd not need a tuned header to realize full potential from a heat engine is in the case of turbocharging where you just want to get the most exhaust gas flow to the hot side of the turbo. After the exhaust gas has spent it's energy in the paddle wheel, you can dump it in a convenient place and you really don't need a muffler as the turbine wheel breaks up the sound waves quite nicely.