Yet another example of how moronic RadioShack can be (sometimes) go to their online site and look at the stage 2 motor upgrade, you will notice that in the pic, the 2 wires going from the motor are disconnected from the black connector!
Did you also notice the white, different plug on the closest motor how about how the pinions are set differently on the motor shafts.
And I still havnt figured out what those red motor plugs are exactly.