Additional field coils around motors

[ConKbot of Doom]

I know everyone always wants more power form their motors, and that we aren't supposed to open them up to mess with them, but if you were to wind additional coils around the motor, could you increase the field strength legally?

I was thinking something along the lines of a series wound or shunt wound coil at first, but those are for AC electric motors, and only go in one direction.

However, if you were to have the field coil on its own speed controller, you could vary the strength of the field for when you need it.

This would be considered a custom circuit, so reading R52 from 2005

Inputs to custom circuits may be connected to the following sources:
Branch Circuit breaker outputs
Speed Controller or Relay module outputs
PWM or Relay outputs on the Robot Controller
Switches, Potentiometers, the outputs from Accelerometers, Sensors, and other additional electronics allowed

So it would be legal to have the inputs of this circuit (the power inputs) connected to a Victor, at least as how I see it.
So it would be setup so that once you hit full power on the motors, you start powering up the field coils around the motor to increase the strength of the motors.

Granted it wouldn't be that easy to wind the coil so that it's field matched that of the CIM, and there already is so much power available, and current draw is allready pretty high. Would it be legal, and beneficial to make a setup like this? Maybe as a big red button for when your in a shoving match or something.