Someone correct me if I'm wrong (I know someone will), but a "Booster" is a car with a slightly different circuit board. The extra circuitry allows it to have a "special feature" activated via the 4ch remote - in this case, the feature is that it RESTRICTS the current going to the motor, allowing the motor to run at lower RPM, slow the BCG down, and make it more manouverable through corners.
OK, most people have taken the original intent and flipped it. They drop say a 3.6 motor in, and run it at the "slow" speed by default, then activate the "boost" and run at full voltage, giving the "turbo boost" effect in a straight line.
End result it more fun
