not sure about the mk3 seat motors, the wiring plug is different on them so you would have to chop it and splice the wires (assuming it does fit, which it may not)
you could go to local scrappies and get a motor from any mk2 seat, just make sure its the same as yours.
you could go to local scrappies and get a motor from any mk2 seat, just make sure its the same as yours.