Cirqiut organisers often say to put more air in the tyres as it causes less tyre wear as there is less tyre on the track.......

but as been said above this will normally only cause problems with handling

I run my nova 5 psi lower on three

Depending on which way the track runs I have less in one rear tyre by 2psi so at Combe the near side rear has less the same for donnington

This took ages to work out adjusting tyre pressures

when cold I run 25 psi and when hot they are 29/30 psi

Also I have seen tyres come off the rim where lowering tyre pressures too much so be warned

Dont forget though to always use a warming up lap....I know alot of crazy mofo's go out on cold tyres and come off or spin on the first corner due to cold tyres especially using slicks

Hope this helps

Si