I have had cross drilled and slotted rotors on my MSP for 5 years now, and I really never felt a difference. The biggest issue is the drilled holes started to crack around the edges. My next upgrade will be Mazda 6 front assemblies and stock rear with some good pads.
Where did you get them from? Apparently centric does not make the drilled rotors for the MSP anymore because they screw up the vein pattern of the rotor. You can get them for the rear that's all. Let me know if you guys have a link to a good set of drilled rotors for the MSP.
I'm guessing you just want them for looks then eh? I suggest reading the material I posted above and save yourself the $$$$
Sloted > Blank > Drilled
Drilled is extremely "show" and thats really it.