What model? There is certainly differences between the models/engines and there can be differences between the years - e.g. 92 400E is a different part number than 93+ and 320s have at least two different harnesses. But I'm not sure I understand what you're trying to get at. Are you looking at a harness that is not on a car? If it's installed on a car the only pertinent question would seem to be whether it's original or a replacement.