From a grip perspective the Yokohama AD08 is the tire to beat. It will beat the Michelin Super Sport around the track handily. I had the AD07's and thought they were a fantastic tire. If you look at any test it puts down the best track time, instant turn in, great feel, etc. However it may not be the best tire for every car as it can enhance characteristics. For example on the M3 it is a real challenge getting it sideways on the track and understeer is more noticeable.

I made the mistake of purchasing the Hankook V12's. Hoping the reduction in price and greater tread wear would be worth the reduction in grip. I was very, very wrong. Big impact on grip with very little additional tread life.