Tires and parts - it's like a race weekend, but with a lot more track time. I'd bring your best, cheapest racing tires (why burn the expensive ones when there's no trophy?), and all the parts you'd expect to bring on a racing weekend. You probably won't push the car as hard (at least at first), but you'll spend a LOT of time on the track. I think it's better to waste time loading and unloading your rig than to waste time sitting around the paddock wishing you had the part with you so you could complete the weekend.

Your auto-x experience is probably great background in car control, and the street school probably taught you to drive the line. I imagine that each region runs its schools a little differently, but...

I went to drivers' school pretty "green" - I hadn't even watched a race on TV in 10 years, and had only seen a handful of SCCA races. I found the school in SF Region to be pretty fast-paced and more of an overview of running in SCCA (and a ton of track time) than an education in how to race. They taught flags and rules and the line. Not much about techniques - for instance, they mentioned heel-toe and briefly explained what it was, but never demonstrated it. I didn't even understand the explanation until I was in the car and tried various ways of positioning the heels and toes of each foot and said "ah-ha! If I do it this way, I can rev the engine while braking! Neato!" I looked pretty dumb trying to clutch with my heel while braking with my toes - my feet aren't that big.

I think drivers' school would have been more useful *to me* if I had read some of the racing technique books before-hand, so that I knew what skills I needed to drive well, and got to practice them on the track.