I talked to my friend who owns the 350z and is helping them set it up, he says there will be a full day of track time (9am-5pm) and the reason it's less costly is because the private club has rented out the track for the day and BP Castrol is co-sponsoring it with them. They are trying to keep it to a minimum amount of groups (based on experience level) with a minimum of 4 runs per group, but it will depend on the final count of cars. They are also capping the total number of cars, but I hear they are estimating for 50 cars. More info as it develops and the cars sign up.
Also, note that this is the pre-registration price by June 12. I think you can contact the guys through their website and they should respond, and if you want to talk to my friend just let me know and I'll put you in contact with him.