I have to agree with Westpak, louvers won't help enough. One must be careful about ducting ventilated rotors, or any rotor, as adding a bunch of air to the inboard side, without adding an equal amount to the outer face will cause warping/unequal pad wear issues. Ideally, we want to duct to the small diameter of the "ventilated" rotor. I have yet to figure out a convenient location of high pressure air.

All of this is only relevant to Z's being tracked. For the street or autocross, save your energy, as it isn't necessary.