You know, I have gone through all sorts of different mufflers for the last 45 years or so. Sound is such a personal preference type of thing and impossible to describe. It's also impossible to advise anyone else or get meaningful advice.
That said, I have finally come to the conclusion, that what I like best is just a cheap set of large turbo mufflers. They flow about as good as anything and have a great albeit somewhat quiet sound. I buy the Summit house brand and get them in a size larger than the pipe on the car, then use reducers on both ends. Using oversized turbo's gives better flow and a more powerful sound. The fact that they're cheap doesn't bother me either.
Yeah those headers are no fun at at all. Three problems I've had; #5 tube runs extremely close if not touching the oil filter (breaks oil down a lot faster when running through a filter that is 700+deg, pitman arm put a good dent in the side of one of the tubes (no hole), and lastly they like to scrape a lot around here bu these are ****ty FL roads.
I'd go with a single chamber Flowmaster or Magnaflow. I have the Super 44s and they r a little quiet for my taste.