I'm about to replace the front pads on my '04 300m with ceramic pads and am wondering if I have to replace the rotors, too, or if I can have them turned. If I have to replaced, do I need to get anything special?
As long as they are not turned below minimum thickness, then yes, you can have them turned. However, the thinner they are, the greater the possibility of warping and/or cracking depending on the quality of the steel.
Get the vented rotors specified for the 300M Special.