[swartzentruber]

Pretty good advice so far. I'd say you'll at least want a helmet, borrowing helmets gets old quick, and not every organization has helmets to lend. It's probably not strictly necessary, but switching to a racing brake fluid and possibly at least a street/track brake pad are decent ideas.

I might get differing opinions since you are a beginner, but if it's your daily, I highly recommend track insurance, unless you are absolutely certain your insurance will over it (and most national carriers won't). Lockton Affinity provides coverage for all (I think) BMW and Porsche driving schools, and others as well.

Also, make sure you have some money set aside for "track contingencies". Things happen at the track, sometime expensive things (even if you get track insurance, coverages have a $2K deductible at least). It's good to have some money set aside in case you need to fix or replace something that the dealer and/or insurance doesn't cover.