Changing alternator for bmw z3?

what is the best alternator for a BMW Z3 and does the amp in it matter?|||You don%26#039;t state what year or which engine you have. You%26#039;re best to go to a dealer. Yes the amp rating matters. The rating can be anywhere from 80A to 120 A, dependent on which engine and what options you have in the car. They will also charge you a %26quot;core charge%26quot; if you do not return your old alternator.