Just to add some notes to this....from the MANZ manual helmets covered nationally are the following:
SA95
M95
M2000
Certified British standard (Blue label)
SFI spec 31.2
E99
Internationally (including NZ)
SA2000
Certified British standard (Red Label)
Keeping in mind it could be an open day in such they don't check your helmet but it's your head. I would think you could pick up entry level for around $300
Someone mentioned running 36psi!! As your tyres get hotter they raise so much so that I've measured 5psi increase in an 8 lap session....I normally start around 28 psi cold
Lots of tools, spare lubricants for everything
You're best bet to improve your track day fun is semi slicks (street legal) and some better pads and water wetter (you don't want glycol based antifreeze as you get told off if yours ends up on track as it's like diesel)
Bring some big hairy balls, you can always go faster than you think
Best thing to do really is buy yourself an e30 race car