2-speed gearing
#4
The biggest problem, might be no brakes. It has to have a one way bearing, on the main shaft and second runs on a centrifugal clutch. So there would be no way to provide braking unless there is a provision to do it mechanical
#6
I think this was discussed a long time ago, but the bottom line is that a 2-speed is very unnecssary in an electric vehicle. Without going into much detail, a nitro engine can benefit from a 2-speed, since you can keep the engine in a rev range were torgue is maximized. On the other hand, an electric motor has maximum torque at low speed. Someone mentioned that a two-speed would probably increase wear on the typical r/c brushed motor, as there is a sudden spike in load upon shifting.