The offset won't be the biggest issue, it's the bore size. E39 uses a 74.1 mm bore, E36 uses 72.6. It's an easy fix. Style 42's are the some of the best looking factory BMW wheels IMO.The z3 2 piece style 42s are staggered at 7.5 inches wide up front and 8.5 inches in the rear. They have a shallow lip up front and a deeper lip in the rear.
The e39 2 piece style 42s are square with all the rims 8 inches wide. They have a much deeper lip than either of the z3 wheels. And as others have stated the offset is much lower.
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