cool thinking
It,s nice to have roots.
I wish I could contribute more to this thread, but the only experience I have is with Bisson on an MVVS 25.4cc gas engine. Engine response was nice too.
Power was decent, A bit too noisy though, but the fit to the engine was quite close. If I had to choose for an in cowl muffler, it would be a Bisson for sure, because that is the one I know and would feel comfortable with.
dB production I estimated (well trained ears) to be about 85 dB(A) at 7 meters with an 18x8 prop at 7400 rpm. 5dB too loud for our field. (5dB is about 4 times the alowed noise!)