The alternator that came in my 2004 325iT is a Bosch 120 A, BMW part number 0124515105. The BMW parts book lists this as a Z4 alternator.
The voltage regulator that came on my car was a Bosch part number F00M145435. According to Bosch technical support helpline, this part number is discontinued and there is no replacement. Bosch helpline said my only solution is a whole new alternator.
RealOEM shows three alternators for my car. The oval plug Bosch alternator that they list is BMW part number 12317519620. RealOEM lists no voltage regulator for that alternator under e46, they list only a rectangular plug voltage regulator that fits the other e46 Bosch alternator. However, when I look up that same 12317519620 oval plug alternator in RealOEM under Z4, they list a voltage regulator 12317515319 (Bosch part F00MA45A45219). If I replace the oval plug Mercedes (Bosch F00M144147) voltage regulator that I am using now, I will get a Z4 F00MA45A45219 regulator.
Do you think I would be wise to go ahead and get a Z4 voltage regulator?