I will replace the shocks first, and see what happens, but I'll do the tramp rods anyway as they have other qualities associated with them, which are good even if you are only trying to eliminate axle tramp.
Velocity, slapper bars work to an extent, but they don't perform as good as tramp rods, and i personally thing they don't look all that good, almost
half@ssed, but that's just my opinion...
With tramp rods the rods push forward and upwards on the car, lifting the nose, and effectively shifting more weight onto the rear wheels, instant extra traction. Also as they are pushing forward on the car, they are pulling backwards on the leaves at the same time, this in effect creates a 4-link suspension, something which is very desirable under any circumstances. Furthermore you can more carefully control pinion angle, something which has also been shown to do damage to sprint times if not done properly.
If you go to this link
chassis stuff, they explain how the various systems work, on this page the tramp rods are named slide-a-link.