The reason of course I brought this up is because of excessive exhaust weight these days with noise rules and all on Race cars as well as Street cars that race on the track.
I thought of a Stainless muff, but to get the kind of weight savings I'm thinking of, it would have to be of a thin wall Stainless which would bring the noise levels up substantially. Hence noise control.
I've noticed that the thicker the muff body, the better the noise retention, hence heavy muffs on the market for better noise decibels.
I'm going to experiment.