South African dealers have a special file for parts for these cars , Theres a guy restoring a 333i somewhere in Durban and SMG , Is ordering the parts for him . I have never met the guy or seen the car , but the spares guys told me that its an absolute headache finding and ordering these parts as all the part numbers are in a big file . I think they have one for the 325is and the 333 as well as some other cars.
Your best bet might be to email a South African dealership and maybe and they could help you find the part . I was also told that BMW , at a price will make the part for you if no longer in production , But its costly . Your in Germany ... Just visit the BMW classic car center , most of our E30 parts are being ordered from there anyway.