Proper brake ducting never really looks good. You need large diameter ducts to get enough air through, and the duct has to allow movement for steering and suspension travel. That means you end up with something like this:
Brake Duct Hose : Air Duct Hose : Brake Duct : Duct Hoses : Racing Brake Duct Hoses
Anyway, the issue with the Z that I can see (although a frickin lift would help) is that there are several tricky areas to get through. Then, in order to get air to the center of the rotor you have to get the ducting to the rear side of the front hub, which is not easy. I think it might require some custom injection molded plastic parts to really do the routing right on this car. Next time it's on a lift, I'm going to try taking a better look at the whole thing...