E30 M40 to E36 M42

[Tomy93]

Hi guys!
I just want to swap my M40 to M42 in my E30. I want to take the engine from an E36 because E30 IS is rare here. I only know that I have to put the oil pan from the M40 to the M42 and that I will need the E30 IS engine mounting brackets. Transmission is the same. I need a little help in the wiring. If i know well the E30 has different pin layout (and maybe connectors?). So what should I do with the wiring harness? Do I need the E36 wiring or the E30 wiring can be modified to get all the things work?
Thanks