There's not much room to add anything and absolutely nowhere to put an offset turbo style or chambered muffler. Just replacing the muffler with another glasspack didn't seem to make much sense. I stopped by a couple of exhaust shops, but no one had a reasonable alternative. Finally, a friend helped me come up with a great solution.
I've posted before and after pictures, but basically we took out the straight section of 3" pipe from the DP back through the tunnel. We were able to save the cat and still have room to weld in a 6" diameter Borla XR-1 race muffler. This is not the sportsman or S type, it's the straight multi-core race muffler. It was one of two a friend had on his Camaro race car. Fortunately, he gave it to me cheap. There is just enough clearance in the tunnel, so it needs to be centered well to avoid hitting either side and giving you a rattle.
The sound is great. Much deeper than I had hoped for. I still get a small amount of drone between 2,500 and 3,00 rpm, but now I have an extra 18" where the original muffler was to add a resonator. And I don't have this big can hanging down under my bumper anymore.