As long as the speed control can handle the motor that your using you should be fine, the quantum competition would be the best if your running a mod motor. I dont think the runner would be able to handle a mod but a stock would probably be ok.
That is definately true, reversable ESC's have a lot of resistance running through them. I ran the Quantom in offroad for some time, and never had a problem with it even running 9 turn motors. Hope you enjoy yours.