Cheapest route is to just replace the rear cats with those $500 Fabspeed bypass pipes. Or else, buy some used ones off of someone who installed those Fabspeed pipes. Unless the cats you're talking about are the forward precats on the headers.
I have the Dansk exhaust, and like it...although I got it years ago for $750 when Departstop was still in business. No drone, but not as loud and aggressive sounding as a GHL or PSE.
Video of Dansk muffler revs:
http://www.youtube.com/watch?v=hdfjWi5LWwk&feature=youtube_gdata_player