I'm invested way too deep to give up. I've put the cost of a basic new car into this thing - that's 2 basic new cars to you Americans!
As soon as the studs sheared off, a spectator offered to change them if I could get parts and tools, so I got a ride home to pick up replacement lugs which were conveniently all in a bag after gathering them from the car the night before. Came back to the track with my mom's 116i to try to set a decent time, but that's when I found out that that changing cars in the middle of the event would be against the rules. So later I drove the 'rolla very gingerly home and arranged for a shop to change all the remaining lugs and take care of the failing CV joint boots at the same time. The car should be ready to pick up this evening, and I've just heard that the new front brake discs are finally out of customs.
The problem with all that is that I'm now even deeper in the hole I decided I didn't want to go any deeper into, this project is now strictly budget-limited. I don't think I can afford to do anything more with the car before the next autocross unless it's 100% DIY with parts I already have...same goes for my Samurai and the offroad rally now, in fact.