Kind of depends on which gear box you have. if you have an 1:1 ratio gear box you don't want an E30 3.73 lsd, you would want an E LSD in the ration of 2.93 to no more than a 3.46 LSD.
Unless you like having it bouncing on the rev limiter. You can also source a Z3 LSD or a E28 535i LSD. Medium case one ear. | 
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