There are two primary objectives for the Autocross.
#1 SAFETY
#2 FUN
You will have more fun running the autocross than anything else you can do in your Camaro... I think I'll stop there. The first segment of this video is a great preview to the course you will be running at INDY.
Here are a few things you may not think are important for an autocross, but...
Sun Screen
Chairs
Hydration -- Lots of WATER
Friends
Snacks
Water
Water
Water