You get to this in uni? Man, the nearest I got was a remote control power switch...

Anyway. Advice:
Print out all the rules- you'll refer to them a fair bit.
Skim through the Rio bot tutorial. Good advice if a little long winded

As for the controller, surely you'd get the similar amount of marks if you just explained WHY you chose not to attempt to building your speed controllers (with the knowledge of how it works) compared to spending the building something that will just blow up and take money with it. It's not the best engineering decision I grant you but it is the best project management decision you could make. If possible, have a quick chat with Ian - he can't make your decisions for you but even his evasive efforts should tell you where the marks lie.

I'll keep reading- good luck!