I have always been told Zimmermann is the supplier of rotors and the only difference is that Zimmermann does not paint the hats, but you can do that yourself if desired. For base 986 owners that like the holes you can get them from Zimmermann, but not Porsche.
I have no clue if Brembo only makes calipers, but you can search on their site.
Here are pads of a base 986, made by Textar and Galfer. I think when Brembo and Porsche put their name or logo on them the price goes up.
