Dan:
Some answers to your questions.
What if something breaks? I have a trailer and I assume Dean does also. We'll load your car into one of the trailers and drive our car home.
Drive shaft hoop - You won't be running your car much harder than on the street so it's not a "have to" for Putnam. If this was drag racing that would be a different story. When you do get a hoop, make sure you get one for both ends of the driveshaft.
Helmet - make sure it's a Snell 2005 (2010?) rated helmet. Motorcycle helmets don't count. MVP's web site has the specifics. They will check to make sure your head is not above the rollbar. It doesn't have to be inches below; just as long as it isn't over. You'll need at least a 4 point harness. In order to convince an instructor to ride with you, you'll need a passenger side rollbar and 4 point harness. Long pants, long sleeved shirt and shoes.
Street tires - they are the best tires to learn on. Unless you were born with Mario Andretti driving skills, you won't push your car hard enough for the tires to make a difference.
What else to check - make sure everything is tight - driveshaft bolts, linkages, etc. Nothing leaking. Fresh brake fluid. I drive mine enough normally that I also get my oil changed before the event.
Extra parts - A tool kit, lead hammer and safety wire if you have true knockoffs, belts, hoses and maybe even a fuel pump (they tend to go bad on SPFs) is plenty. At Putnam you're 30 minutes from Indy and there'll be plenty of people with tools and spare parts that are happy to help.
Be prepared to have fun, to spin out and even leave the track. At Putnam none of these things are a problem.
The next part is probably worth a separate thread - Insurance. The vast majority of policies will not cover you at any event like this even if there's no "timing" going on. I have insurance through Continental Western (CWG). They will cover these High Performance Driving Events. The SPF I'm driving is my second one. CWG paid to replace the first one when I was rear-ended by a soccer mom. They're a great company. I think everyone in the club should be using them. No, I don't get a commission. I'm happy to field any calls or questions on this.
Steve