RE: small or big tires
Slicks for sure, really wide and very tall tires for the read if 2WD, and small skinny one on the front.
If you have 4WD, go with slightly wider ones on teh read and slightly narrower ones on teh front. When accelerating, teh center of mass of teh RC will shift rearward thus placing more force on teh rear wheels (by way of the same action that eventually leads to a wheely, with teh assistence of the engine's torque on teh rear axles). But in 4WD, make sure all 4 wheels have the same diameter.