Hi,
My friend (and ex-boss) PJ (Peter Johnston, director of Rally NZ) has been doing private track-days (actually track afternoons) each month for quite a while.
I have talked recently with him about extending invitation to Toyspeed.
Location: Hampton Downs.
The cost is somewhere between $60 and $70 (depending on how many people), in summer the trackdays start at 4pm, in winter at 2pm. Runs until sunset. This all depends on weather of course.
All you need is a car and a proper helmet (motorbike one will do).
Let me know if you are interested.