Maybe you might like glasspacks? Seems like people don't run them on newer trucks. I like Flowtech Purple Hornies, they have a nice sound and the louvered core is not as restrictive as other glasspacks. Idle and cruise are nice with no drone, but they get pretty loud at WOT which is nice.
http://www.summitracing.com/parts/BIG-50225FLT/ You could get a 3" to dual 2.25 and run a pair. Never ran them like this or on an LS motor but it sure would be different.