Genuine BMW part 41 00 2 355 972: Set, threaded inserts M5. The number stamped on the part is 41002355972; BMW's catalog files it under the short number 2355972. You will find it on our Exterior Body shelf, under Other Bodywork parts.
It fits every E46 body style (320i, 323i and 325i, 1999–2006), with the M52, M54 or M56 engines — and the European-market versions.
BMW draws it on 6 diagrams, among them Repair kit, thread repair (41_2559) and Repair kit, thread repair (41_2560). It weighs about 20 g (under 0.1 lb).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.