I pumped mine up to 40 (cold) before I left Canberra and then adjusted them once we were there to about 36 (warm) because the track is at a different altitude and once the tyres are warm the air pressure is different too.
For track work its advisable to pump your tyres up a fair bit to stop the sidewalls from rolling excessively during cornering but there comes a point where you can't stop rolling entirely. Have you seen the pictures of V8 Supercars where the camera is on the side of the car looking at the tyres going around corners? scary stuff!
Tyres with too low inflation can be a big problem. I did a defensive driving course and they showed us a skid mark from a falcon with tyres inflated at 25psi. There were two black lines from the sidewalls of the tyres and nothing in the middle. Went to the servo and pumped them up to 34 and did it again and there was a single thick black line about half the distance. More tyre in contact with the road = more friction = less stopping distance.
Its the same type of equation with cornering.
