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I didn't see this part in the interchange FAQ; it's another question best fielded by someone with multiple BMWs.

I'm expecting wide interchangeability across M30 engines. I did notice different part numbers for the E12, E28 533i, and E28 535i as the M30 evolved. Anyone know what was changing....weight, pulley diameter, more sensors, etc......?

Weight, and I think in relationship to crank throw. Pulley diameter may be another factor, but I think it was really about 71MM, 80MM or 86MM throw on the crank. E28 M5 may be another factor with it's 84MM crank.