I am currently running a set of 14 inch A539 series Yokies in sprint races in Oz. They are also the preferred tyre by a number of other drivers. Overall comment, they are a good tyre which are pretty responsive. Seem to squeal a bit (so do a lot of other tyres) but the best thing is that if they are starting to let go, they let you know. My biggest problem is that sprint races are short events (4 laps of a 1 mile circuit on average) and they take a bit of heat to get working well. Once hot you can really tell the difference. The A008's are still pretty popular here in Oz. Biker