Just been talking to the nice man at Pirelli and have talked myslef into getting a pair of Diablo Corsa's - good for road and track apparently.
Std rear for my 93 ss is 170/60 but he confirmed a 180/55 is good and matches the front OK (and that a 170 is not available for a Diablo Corsa)
He reckons tyre pressures should be 36F/42R and pressures should be dropped between 3 and 4 psi for track use.
I can almost hear my credit card crying in the background
Frank