I have been DE'ing my car for three years and know some of the basic answers to this question, but thought I would post and see what the long-term track guys keep in the spare parts bin.

Also, every summer, I try to get up to the Glen for 5-7 days of straight track time as various PCA clubs run one after the next. Here's what I bring now in terms of spare parts, and here's what I have been caught short not having in the past:

Bring:
Tires
Pads
Rotors (if they are at all worn)
Brake fluid
Oil
Coolant

Caught without:
F-hose (my original one split)
Radiator (blew left front at 155mph, fortunately on the back straight)

Thinking about bringing:
spare MAF
???

Any words from experience would be appreciated, and maybe save my day/week as I am a reasonably good DIY'er.

 

A cheap spare but a show-stopper; serpentine belt. Not experienced personally but I remember seeing one break during track testing of the GT2 on the UK "Fifth Gear" show.

 

Power steering fluid might be a good idea, doesn't take much space but the noise it makes if its been sweating and is low will freak you out. Pentosin 11S if I remember correctly