Drilling holes allowed?

My students have a C-channel that was bent and in order to secure the piece to the base platform, the holes are a little off and they are asking if they can make the hole bigger or drill a hole to match exactly where they want to mount and fasten with screw. Is this allowed?

Yes, this is legal. You can also cut C-channel to desired lengths if needed. Drilling holes is also required to use high strength axles in most situations.

Yes. Nearly every part in the EDR system can be mechanically altered to your heart’s desire (with the exception of the electronics).

EDIT: Here’s R16j:

Thank you both, much appreciated.