CSX,
You want mufflers that work and are nice sounding and flow well and sound way cool with an X? I'd avoid any chambered mufflers (relatively high sound level) and they flow not so well.
Instead, look at the Goerlich XLERATOR X118. They will flow more than most anything, be quieter than most anything but the Dynomax SuperTurbo and at 18", they are a direct fit on A-Bodies.
Next in my list would be MagnaFlow 18" versions.
Or, if you can fit them, Dynomax 17748's are great but at 20" long, they are tougher to fit (shot below).
If you were rich, buy these VOE mufflers from
www.waldronexhaust.com
Tom