I went with this set-up for sound, not power really, since IMO both the V6 & V8 are adequately powered for the purpose and intent of the Pathfinder.
This is with the Cajun B-pipes. (Purchased from KnightOwl on TitanTalk forums). and a Magnaflow PN 12558 (18" body).

http://www.youtube.com/watch?v=ukNzyg5sDag&feature=plcp