If the caliper fits the stock rotor, it will also fit the z4m rotor. Offset is the same afaik.
For the 330i there is even an official perforated rotor upgrade which is basically a z4m/m3 rotor but in 325mm dimension (but with the same aluminium hat and thus offset etc):
http://bmwfans.info/parts-catalog/E4...ted/#2282871_1
Needless to say this rotor also fits the z4 3.0si stock setup.
The big problems are at the rear where the z4 has a big offset and the smaller parking brake shoes (160mm), so no other rotor/caliper assemblys work unless heavily modified.