Re: taking resistors off or shorting them - yep we used to do that back in the 80s when racing. Theory was at the time that when racing you should be "blipping" the throttle rather than applying one of the 3 speeds, & obviously it takes less time for the servo to find the 1st plate on the MSC than the 3rd, so make that one "flat out" (& the others so there's no having to "select" the beans, any throttle stabbing gives flat out).
This was usually done to remain competitive with the rich folk who had ESCs, of which most were rigged with a button on the Tx to give flat out throttle blipping rather than having to wait for the ESC to wind up to speed.
