Believe it or not, most road race guys I know, as well as myself, would recommend staying with OEM rotors. Any upgrade from there would be to Brembo blanks. I'll even go one step further and say that I know of some ITR guys who see frequent track use who purchase the cheapest rotors available from Auto Zone. For $40, I did the same and have had these rotors on for over a year. Any wear noticed makes it cheap to replace and I can stock up on them because of the low price. While I do not know all of the exact details of why slotted/drilled is not the best choice (gas expansion, cracking, etc.), I have found that using OEM rotors is the most economical method, and allows me to spend more of my money on top notch pads. Most people I know who do the same thing I do would say that you're not really going to see any increased "performance" from a rotor until you say upgrade to some exotic material.