Newer racers who might be reading this thread need to know that there is a difference between normal play in the moving parts of the car and excessive slop. Because most r/c cars weigh so little, they need to have at least a small amount of play or "slop" so that the moving parts and/or suspension can work properly.
Before you set out to eliminate all slop in any r/c car, make sure you understand how the suspension/moving parts are supposed to work. Make sure to test those parts under a load after you remove any slop to make sure they are still working freely.