I purchased and installed a Scottsdale dual exhaust system. They have a straight through glasspack design muffler. (really not a muffler doesn't have enough of a twist pattern in the slots). Anyway, it is a very low restriction system. 2.5" mandrel bend and a set of polished stainless 3" tips (no baffles in tips either). It is a bolt on replacement system. Low deep sound, sounds nice@ 3000rpm also. Does get a little loud when you hammer the pedal. The only drawback is that it is not stainless steel. I'm Happy with it.
Pic Below:
Alan