I went from the stock Michelins to the Khumo Estca 712 and I can't say level of grip is that much better. The XGT's cried on every corner but they still gripped pretty well, Khumo's are much quiter but I don't feel they have more grip. They are better coping with heat, after some hot laps on the track the Michelins were chunking while the Khumos looked pretty good.

Just my $0.02.