If your back end is bouncing you are using too much throttle. Nissan went to a softer 2 leaf spring set-up in the back. The problem I have seen is that the springs seem to wrap-up easier then the older models. Stiffer shocks could help this but I can not verify this as I am running 01 shocks on mine (busted the 02's off-road beginning of summer). They may also keep the vehicle from nosing up during heavy acceleration.

ALAN