To add an element of strategy, I used the repair robots to enable/disable the tower. Previously the repair pulse only fixed vehicles, but now the tower will respond to a repair pulse by stopping its scan and firing.
Another possible future option would be for a repair robot to repair a disabled enemy unit and "claim" it for the friendly side.
Note: I hacked up this rumble robot pretty bad. The problem ended up being old AA batteries. It needed fresh ones. The way their motors are geared, they don't behave well with marginal batteries.
I ended up adding a TIP120 (NPN transistor) to the arm movement because I couldn't find the pin that controlled them. If anyone knows where this pin is located, please send me a .jpg...thanks.
Most people place their rumble robot controller in the head, but this requires that the arm motors be removed. I kind of liked the arm motion, so I had to place my controller on the outside of the robot...Not very pretty, but the arm motion is cute for simulating the repairing of the vehicle.