After testing I have done up this fact sheet for the cars. This indicates at what voltage I will be running your cars to get the best laptimes from each chassis. I will be running all my cars and a couple of others at the 13.5 volt max. In my case the Minebea motors are 17k at 12 volts and they are slow at this voltage. The extra 1.5 volts perks them up and the motors themselves have zero issue at the higher voltages. A couple of other cars also demonstrated this.
The other cars have voltages selected that make them drive able and are turning consistent laptimes without being squirrely. These voltage selections were based on laptimes generated during practice, and the voltage/car/Tire combo resulted in the fastest lap. I also discovered that the Carrera system I am using has an inherent indicator for determining the right voltage. It seems anytime a motor is being overdriven, the electrical interference it creates has an effect the IR in the Carrera digital timing system, and causes the system to "beep" I am not using this system for timing these analog cars, but I found it interesting that when the motor voltage feels about right the Carrera digital IR is happy and makes no noise. Maybe just a coincidence but it seems to be true.
If you have any comments or concerns about this wade in and let me know. This is being done to get the optimum times out of each car entered when it is racing on my track.