[EricH]

The controller would be counted as a custom circuit, and must follow all the custom circuit rules.

VEX motors would be illegal except for up to two of part #276-2177 (per [R48-H]). (Or VEX servos if they fall under [R48-L].)

All other VEX parts would be legal if they met the rules.

Game - The Robot » Material Utilization
Q. Can we use VEX parts on our robot?
A. There are no rules expressly prohibiting any particular brand. Please note that there are many rules regarding what specific items may or may not be used on the Robot throughout The Robot section of the Game Manual.