While I know nothing about SP myself, I'll say other than the 'slotted only', their rotors lost a TON of surface area. Those chamfers on the drilled rotors are enourmous. Way too extreme. If you do something like the diamond slotted, you better plan now on a larger diameter rotor to make up for the surface area you lost.
Their claim that the diamonds give the same effect as drilled is ridiculous. The idea of crossdrilled rotors is (generally) to use them for one race, then throw them away, as the air travelling THROUGH the hole cools that surface more rapidly than surrounding areas. It cools the rotor quickly, but also stresses the rotor in a very short amount of time.
Have you read this recent topic?
I'll move this one to Performance and Brainstorming as well.