Soren, I took a stock America muffler and gutted it out then i took 1.5 inch pipe made to ends to hold it center. I then cut semi circles and bent them up so i could create back pressure. It seems to me the more i cut the lower the tone. The packing deadens the sound. I agree you are treading on uncharted territory and it's going to be a process of trial and error. I'm running Epcos now I just never did like the tone. I used string wrapped around the packing while i put the assembly in the Pipe, it just burns off mostly.
