Removing a leaf from the springs will give you a little smoother ride but will reduce your load carrying capacity. As Brendan says the tires are the best to change. As your truck goes down the road the small cracks, lumps, and bumps are almost entirely absorbed or transmitted by the tires. Old 6 or 8 ply, high pressure, bias tires are very good at transferring these jolts through the springs, which do not flex much, directly to your back side. Radials can carry the same load but will deform easer to absorb the impact. The springs come into play when you run over larger lumps and in Michigan POT HOLES. The shocks really do not come into play except to retard bouncing of the axel as the springs like to bend and rebound.
