You don't "need" them, but at the very least, I would get the drop pitman arm. It all ties together with the steering geometry. When you lift your vehicle, you move the center of the axle to the driver's side. The trac bar riser or a lengthend/adjustable trac bar corrects this. As for the drop radius brackets, those are completely unnecessary unless you are trying to use original degreed "C" bushings and are not using the bushings that came with your lift.