Brembo makes good quality rotors but they seem to be more prone to warping.
We sell a lot of Zimmerman rotors for the 330 and we've never had any complaint. Zimmerman makes
plain or
cross-drilled rotors.
For normal street-use, I would stick with plain rotors.
Warping a rotor is not that common. Are you sure your rotors are warped? A lot of different things can cause a pulsating brake pedal and/or a shaky steering wheel.
Read this if you want to know more:
http://www.stoptech.com/tech_info/wp...rakedisk.shtml. It's very interesting.
The most common problem is pad material deposits on the rotor surface. A dented or unbalanced wheel can also give symptoms similar to warped rotors.
Before replacing your rotors once again, make sure that they are warped.
Karim.