Because your not behind the car hearing it.
Chambered mufflers sound like ass anyway you slice it.
I have been behind it and heard it take off. It is not much louder. Sounds almost the same just a little deeper but definately NOT loud.
I heard a '99 with those and a res delete, wasn't ass, but too loud for me.
ANY...and I mean ANY 3800 with a resonator delete...that isn't snail'd...sounds poopy. I'd bet money on it you couldn't find one resonator less FWD 3800 car that doesn't rasp.