This would be a practise day with timing.
You can push your car as hard or soft as you want. If someone is hassling you, you could speak to the organiser, they'll probably be able to have a word with people (If it's like the track days i've been too).
My car is never 100%, still got heaps of things on my to do list but practise one of the best things you can do.
BTW, Circuit = Yawn, drifting = fun .