Restrictive Mufflers

[MoparDaddy]

I have these in 2 1/4" and I think they are quieter than the turbo muffs that I had on there before. Full Boar also makes a chambered muffler.http://www.fullboarperformanceexhaust.com/servlet/the-template/fullboarlineup/Page

Seems like the exhaust gas just runs in to a wall with a chambered muffler. I like the sound, just not sure about the performance. I'm sure this has been gone over, but could someone enlighten me?