Don't know sorry, do a search I'm sure skylinegeoff has mentioned it a few times, along with some other people, there is more than one place... if you can't find one drop me a pm and i'll ask my mate for you.
INASNT: I have the same tyres on my car - hankooks - 4 track days and i think about 20,000ks on my hankooks and still going... no chunks missing, and still another 10,000ks on them i recon. Mustn' be driving hard enough.