This to add to my previous pictures.
The dimensions are as follows:- OD of rear tube = 1 13/16" (46mm) length of tail pipe = 3" (76mm) length of baffle = 6 1/2" (165mm)
The front pipe is 2" (50mm) OD and the bit that is squashed like a reed valve is 3 1/4" (82.5mm) long. Ron
Overlander already make M20 mufflers in stainless and Barry will put any baffle you like in there
http://dropbears.com/overlander/
Make you a matching M20 exhaust pipe in stainless as well.
A couple of my bikes are running his systems.
The A65 has decibel copies complete with tuneable outlets which have been on it since 1992