I was led to believe that most 87 528e's have an LSD...true? And further to that, will it work with an E9 without major surgery? Sorry to be such a mechanical zero..
Little correction - E23 from the very beginning had completely different type of diff if compare to other same production years BMW models.Yes it might have an LSD, no it will not fit without major surgery. Totally different mounts, subframes, and sizes. You would need to change subframes, trailing arms, etc...
It will cost you less money and less hassle to find an LSD out of an e9, e3, e23, or e23.