Does the mechanism self-park? Mine parks with the arms toward the driver's side. Yes, power from the key, you only want it to work with the key on.
Follow a Bug wiring diagram and double check the wiring from the motor to the switch. I ended up taking the motor apart, cleaning it and greasing it up. Works fine now, but popped a few fuses until I sorted it. I only had one power and one ground.
Yeah, it sucks getting under a Spyder dash, I AGREE!