I've run around the track no problems.
Just bring what Wakefield tell you too and make sure your car is in good nick. Also, as Luke said, don't keep the car going hard for too long or shite will break. Take rest breaks for the car. Brake pads are probably what I keep an eye out for the most. As for petrol, if you'll be running the whole day then maybe take some extra, but you can always just drive back to Goulbourn (5-10 minutes) and fill up at the BP/Shell there. I personally have driven to Wakefield, done an afternoon of laps and driven back on one tank.
Just keep in mind that you drive to your limits, don't worry about faster people on the track as they will overtake you on the straights, just move to the side and ease off a bit to let them pass. I've seen one guy drive beyond his limits and he put his SS Ute into the wall (freak occurance but still....).
It is immensly fun however, so go and have fun!!
Leigh, I ran around the track at 14.7psi and had no problems, this however was during the colder months so keep in mind temps will be higher.