Man, I really don't want to spend another $150 on rx's.

So let me ask this way (because I'm just a weekend hobbiest, cost is a bit more important than features)...is there any way to use the RX's I already have - they are the run of the mill RTR radios - a Team Durango, Axial, Dromida, and Tactic.

The only feature that I want to have is the ability to dial back the throttle so my son's can drive the trucks/boats without injuring themselves, others, or the vehicle!!