RadExpand bypass speed limiter

How can I bypass the speed limiter on a RadExpand 5?
Like most of the bikes on the market today the manufacturers are limiting the speed via the controller. Some but very few allow you to modify the amount of current/amps the controller feeds to the motor. But the speed of these brushless motors is determined by how they're wound at the factory and only by increasing the voltage of the battery can you see any substantial increase in the maximum speed.

I would suggest a call to rad's tech-support see what they say.