Hey Pete, Yes shim the diffs. You want about 30,000 in the front and about 10,000 in the rear. Think of it like a front wheel drive car, when your driving in a curve you don't want your inside front wheel unloading, you want it to pull through the corner. So the heavier weight needs to go infront. What weight oil do you have in the shocks? Is your truck too stiff, common mistake. At rest your front should be level and the rear just above level. Don't cofuse ride height with dampening. Springs and oil work together but the springs control ride height and the oil controls dampening. Too heavy springs and not heavy enough oil will make a sloppy bouncy truck. It takes time to work out what will work for you, I like 35 wgt with black springs with one shock per wheel (not big bores) and I like my shocks inverted, it puts the weight of the shock body and oil lower next to the wheel. Yes steering bearings. The radio is your choice but anything is better than the stock. And all the set up in the world won't make up for practice and stick time, I'm living proof.
See ya at the track, Joey