For heat problems, try some Artic Siliver between the motors and mounting brackets. I don't know if it will help in this instance, but it lowered my CPU temp 8-12%. Someone want to give it a try and see if it helps?

Artic Sliver

The expoxy I is a fastener, and is allowed under the Addional Hardware. Doubtful about the others.

Current Limits
 

We are using the Chiaphua motor for drive with 4wd.
With ~14:1 reduction and 10" wheels we get about 15fps.
Acceleration is good. When spinning the drag is quite high on carpet so you have to take it easy. When pulling the goal, don't accelerate fast and you will get to full speed. A custom circuit and special code will be used to protect the breakers.