Originally Posted by ALEX.

I think a lot of it is down to preference once you are set around the optimal pressure for a given situation (eg track or road driving). It depends on the tyre, its profile, the car and also your preference! Like Kato said, changing the differene between front and rear CAN yeild different results in terms of how the rear end feels. It's all about finding the results you want.

Personally I have run around 36 in both tyres for the road (i have Fuldar 225/35/R18). When it's time for hard slogs, it goes to about 40 in F+R. I still need to expeiment with the difference in changig the front and rear pressures. But i do know that lower pressures on the back for our AWD Subies can make them slide out more than if they were more the same pressure.