I used the brake caliper paint to paint my rotor center (hat) and the ends of the rotor plates and the fins in between. I used just cheap, flat black, high-temp paint for the insides of the hat and the area between the rotor fins. Actually, I did the inside first, the sprayed the fins from the outside. It was a PITA, but it turned out great and still looks great. BTW, this was on my Firehawk, not the Boxster. Here's a pictures of the results (please ignore the dirty wheels) while the car was still on the jackstands.
That's the rear wheel where you can see the center of the rotor better. Here's the front wheel where you can see the edges of the rotor and the fins better.
A friend of mine did his on his 'vette in silver after he saw mine, and they turned out great. He wanted silver so they would just look brand new and clean. If you use the caliper paint, it will be high-gloss. Keeping them clean is a PITA though.