I would shim the diff's. All of my RC's are/were weakly shimmed from the factory. I am starting to put 100,000 in mine and am liking the lack of diff steer. It depends on where you are driving and how. I slide my truck a lot and don't want a lot of diff'ing (is that a verb?).

Shimming is easy - take the diff apart, clean it and add shims to minimize play but leave a little play. Its sort of qualitative to judge - adding too many is obvious and you will feel it when you put the shim together. If you add shims incrementally and assemble the diff between (press it together, you don't have to screw it down) you will feel improvement and know when you went over. Not very scientific but effective.

I installed flat-iron tires, .5 inch taller than normal and put on a 13T bell - the rollout is actually slightly shorter than I thought because the tires weren't as big as first thought. It looks cool. RCDAMPER on ebay is sending me free springs for the truck because the spring rates were ridiculous on the ones they sent me.

To all the PM's - sending out the rollout sheet shortly, just need to clean it up.