I was at Donnington doing testing on the tyres last week with the help of Malcolm Edeson (Grade A ARDS with around 20 years of race driver instructing ) He rigged up one of the mx5 championship cars with all the data logging equipment and went out to prove what the benifits of shaving are. He his writing up a detailed report on his findings and I will put it up as soon as its done, the main thing he concluded with is that its worth about 1.5 seconds a lap!