I would start with the rear trac bar and the konis(and in that order). On ours, the trac bar helped with steering corrections for cross winds and passing trucks(tail wag) and the Koni FSDs took care of continual porpoising and sway at bridge expansion and pavement joints. IIRC, the cost was $450 and $650 respectfully. Bob
Note: I installed the BlueOx Tiger Trac and the rear shocks myself...my worn out body and wimpy impact would not budge the bolts on the fronts. Paid a big guy with a big impact wrench $60 well spent bucks.