A word of advice from my first trackday experience (a month ago at EC). Don't worry about how fast you can go, just make sure you can stop. A good set of pads and -really- good quality brake fluid is a must. If you can't remember when you last had your brake fluid changed it was way too long ago (as I learnt). Go and get the 300+ degree's stuff ($100 fitted) and a new set of front pads.
Its quite scary going into a downhill hairpin with your brake pedal flat to the floor (lucky it was on the cool down lap and i was doing 60km/h around a 70km/h corner).