Sorry but I have to disagree with the above comments, cooling is of huge importance, especially on a track day car, lap after lap of flat out driving, would almost be impossible to compare to fast road use! being stuck close behind a car that you cant get past will drastically cut clean airflow to your radiator, I would definatley look at a more effeiciant fan, and also wiring up the circuit with a switch that can manually overide the thermostatic control, or an adjustable thermo control, where you can set the fan to come on at a lower temp, this will give your engine more time to recover after a fast session
Also not to be overlooked is oil cooling, this is a must! fitting an oil cooler helps prolong the life of the moving parts within the engine.
On the subject of oil, also worth considering, is fitting baffles in the sump, this will eliminate oil starvation on long sweeping bends..
All of the above could be done for less than £300, and may mean the difference between driving home from a great day out, or being towed home with a compleatley shagged engine!!
Tom