To me, the chambered mufflers sound too much like a glass pack. I have V-force's now on my 79 and they are basically a flowmaster clone. They are way too loud.
I'm going to go with Magnaflows and an X-pipe. From what I've heard from that setup, It has a more exotic sound to it, quiet at idle, but smooth/loud at WOT, kind of like what a factory LSX engine would produce.