Hankook RS2 best tire I have driven so far especially in the back. very predictable at all temperatures. The tires tend to get hot on the bimmer. fairly priced and good grip.
which bridgestones? try edgeracing.com im sure they can do better than that, oh yeah me is runnin falken rt615 which are good if they are properly heated but lick balls in the wet, they are also not that great with the short runs most of the events we have, by the time you get back on the track they're cold which led to a bit of the UNDA UNDA at OSW2, something which the ziex 512 i used to run didn't do
rt615= summer/dry roads, ziex=all season/rain dori