Steering: if your car turns right whilst turning the steering wheel left (or vice versa) - turn the steering wheel to its maximum deflection in either direction and hold; simultaneously press and hold the steering REV button and the steering channel will be reversed.
Throttle: if your car runs back whilst pulling the throttle trigger - with the car inverted (wheels not touching the ground), press the throttle trigger down to its maximum position and hold; simultaneously press and hold the throttle REV button and the throttle channel will be reversed.