Hankooks stick very nicely, but the R6s aren't the right tire to autocross. Tirerack calls for about 180 degrees before they really get sticky, and with our short runs, they never get over 125. Only Hoosier has an autocross compound for 19" wheels, so next year I'm putting A6s in the rear. What it has done is taught me how to drive a car with a loose rear end. Imagine a Crossfire that DOESN'T understeer. I couldn't break the rear end free last year at all, but I do a lot of throttle steering this year. So far, I'm in first in "DS" in the SCCA club, and I moved up to "D" in NASA and hope to finish in second. If I stayed in "E" in NASA, I would have finished first as well.
Mike