Here's the schematic from the spoiler, You can probably make up a circuit to control it.. but I'd be willing to say the SRT BCM doesn't support it, if there are spare pins on the SRT BCM you might be able to make it happen. I'd imagine the spoiler would go up/ down based on the direction the current flows through the motor and stop moving when power is not applied to the motor (when limit switch is active).

I'm not good enough with electrical to really help you with this, but you should be able to use an IC to control it based on wheel speed. For example, if pin 1 of the IC was the wheel speed voltage, pin 2 was the signal for power to send motor up.. you can make a program that would pretty much say "if voltage on pin 1 exceeds x Volts, activiate pin 2". Can anyone else (Rudy ) expand on this?