I've heard a couple accounts from people who have had 2 speeds in their electric cars and from what they say there is no benefit. Since an electric motor has basically a flat torque curve there is no need to keep the motor in a certain range of RPM like you need to with a nitro engine. An electric motor will basically accelerate the same from 5000rpm to 10000rpm as it will from 15000rpm to 20000rpm (on a dyno of other device where load doesnt increase with rpm like it does in a car). Not to mention this device is going to add weight and make you motor stick way out of the back end of your car.
