I won't lie, it is expensive, but I ran a rsx-s shorty header, rsx-s resonated test pipe, and a Fujitsubo RM-01 cat back and it was pretty quiet. The shorty did bring me down 8 whp, from 220 to 212, but it was worth it in the end. This was my '05 EP with the Fujitsubo exhaust.

http://www.youtube.com/watch?v=l2wSr9djK1Y