Yes, Rara works for Ford Motor Company as a Design and Release Engineer in the Brake Department. I used to work in the same department. I now work for Brembo Brake Systems (you may have heard of us, we have a small reputation
). Mercedes does not use cross-drilled rotors as an OEM part. I know, because we make them.
As Rara said, there are times when x-drilled rotors make sense. In those cases, the parts are designed with the holes in mind. Taking worn out stock Mystique rotors and drilling them yourself is at very best, a terrible idea. If you want to know more, please search and read the number of posts that Rara, myself and MFE have covered this topic. I don't have it in me to do it again today.
-Todd
