Wow! Laguna Seca for your first DE. I am jealous. I have run with PCA-GGR several times but not at Laguna yet. They are good people and a very "safety first" group which is a good thing.
Every group has rules that are specific to them and it is important to be in compliance so you will be able to run. I suggest having your car pre-tech inspected by a shop familiar with GGR requirements in your area to go over specifics. Also contact their Chief Driving Instructor John Tavernetti (johntavernetti@yahoo.com) and explain that this is your first DE and you want to do it right. Perhaps he can assign an instructor in your area who can walk you through the process.
GGR is looking for 3 things: Good cooperation with others, good car control skills, and high safety awareness. If you display these things you will have a great experience with GGR at one of the most amazing racetracks in the world... Laguna Seca.
Have a great time!