I HAD a set of cross drilled- Auto Stop's, put 4 track events on them then they disinigrated in an emergency braking on the road. Shattered the left front and cracked the right front. I'll bring the pieces to SZ if anyone wants to see 'em. Still have the drilled on the rear, but never again on the fronts-- full faced, cryo treated from now on. If you look closely at rotors on cars in Grassroots, you'll see more full faced than any. Not sure about 20%.
