Print your own plastic parts for your VEX robot- these models have been downloaded from the official VEX website, then modified to be 3D printer friendly.
Since they are identical to official VEX parts, these parts are allowed to be used under rule R7 clause b. "Any parts which are identical to legal VEX parts. For the purposes of this rule, products which are identical in all ways except for color are permissible. Note: It is up to inspectors to determine whether a component is “identical” to an official VEX component."