Sibbat, a lot may depend on your serial # also. Is yours a 100+ car or below 100? This may help us help you. Sadly, I'm unable to answer your inquiry directly but others might. Good Luck.
That's a good question.....I was trying to figure that out as well when I was getting my front A arms powder coated. There didn't appear to be any markings on the ball joint so kind of hard to identify.
However, after some checking around it appeared as if the ball joints are from early BMW M3 ('88-'92).
Hi Cliff, I replaced a lower ball joint on my Honda Civic, looked just like that picture, so fwiw I think these may be widely used mass produced items supplied to the car industry and BMW or Audi may not be the only source.
Dave