Regarding fuel, you might not want to run with a full tank because of the extra weight. Most tracks will have a fuel pump, but it's likely to be more expensive than a normal filling station. Take a spare can of petrol, but make sure you remove it from the car before going on circuit. Have you got your own helmet? Some tracks require you to wear a full-face helmet if your car is a convertible. Tracks also do noise checks on each car, but you should have no problem with a road car.
