Rambunctious muffler recommendation

Since you are not planning to race with the mufflers on, just wanna quiet it down for occasional street use, i wouldn't spend big money on mufflers. I would get a pair of summits two chamber flowmaster welded knockoffs, thirty bucks apiece, a couple lengths of pipe the same size as your collector(assuming 3") a couple flanges and a couple hangers. Done
A little tougher if you have 3 1/2 collectors. Either you will have to use a reducer, or find a 3 1/2 muffler. (I use a 3 1/2 aero chamber set, and a 3 1/2 flowmaster, but i bought both when they cost half what they do now, and i race through the mufflers)