I replaced the 2003 model steering rack bushings with Nissan factory replacements for about $16 ea. from Amazon. It took 2 people about 1.5 hrs. The left side (driver) Nissan bushing has dimples on it that provide extra grip on the rack that after-market bushings may not have. And for the same reason, I don't think that hard and slippery polyurethane would be optimal here. The new bushings did correct a litany of steering issues with my truck: It would wander down a straight flat road, the faster you drove, the worse it would be. Hitting a bump or pot hole would cause the steering to shake considerably, and worst of all, making a turn across the concrete gutters that we have on minor intersections here in the PHX area, or over a rounded curb driveway, would make the steering saw back and forth. If you are having the same symptoms, I recommend replacing these bushings.
The old bushings with 123K mls, all in the hot, dry climate of the Phoenix area were intact and looked OK in place. But once they were removed, you could see how much most of the bushing was permanently compressed from the areas where the original thickness was intact, and how hard and not grippy the rubber had become. A similar hardening effect had occurred to my
front sway bar bushings:
For the 2003 model, we had to unbolt the A/C belt tensioner (and tuck it above the center of the rack - it has wiring that is cable tied to it, and difficult to detach) to get to the upper left (driver) side bolt. Before loosing the tension on the belt, tighten it bit to see how much tension to put on it upon reassembly. Unbolt a couple of hose clamps and the oil filter spill drain so that the rack is free to move. We were then able to use a breaker bar to loosen the 22mm bolts, lever the rack from the back half of the brackets, remove and install the new bushings.
The FSM recommends a tightening order: driver side first, bottom bolt before top, then passenger side, bottom bolt before top. Torque: 157 - 186 Nm (16 - 18 kg-m, 116 - 137 ft-lb)