Use two slide dimmers to 2 different channels for right and left power and steering controls.
: Build the Lego chassis.
Build a Lego base. The motors, wireless receiver, and power adapter will be on the underside of the car, but the battery will be hidden under the driver's seat (which is what I did but put it wherever you want) or somewhere else on top of the car. Make any features you want (I did wings, but you do whatever you want). Just make sure everything can fit and the car isn't to heavy. Pick any wheels you want, but make sure they have grooves in them. The rubber band will go into those groves for AWD. Use a Lego converter to attach to the motor.
: Making the car electronics.
Connect the power to the wireless receiver which connects to the motors (make sure the motors are set to variable). Mount everything to the underside of the car using Lego adapters and hide the battery somewhere on top of the car.