Well, what I have read is they can crack, I mean, you got holes drilled all over the surface. The downside of using drilled rotors is that all of those holes tend to weaken the rotors -- just like punching holes in the wall of a house would weaken the wall. After repeated stressful driving, the rotors can even crack. Dimpled is ok, slotted eats pads. Yes, autocrossers run them, but they also change them after every race. I'd be concerned about the longevity of cross drilled compared to solid rotors. Personally, I'm not out road racing, so I have no need for the cost of high performance brake parts. By all means, do what you want though.