That is a good point GT on the noise level. I am thinking that redirecting the gases where they have to go through the perforations in the tube might make it quieter. I could also add some baffle easily.
As far as time, I can whip this thing up in a half hour pretty easily. I already got the shell and inner tube. Just trying to figure out how to route the gas. I have a PM going with someone who has done some small muffler design so we'll see what he comes up with.