Engine Wiring Harness for a 3.8L

[insaneABOT]

Well guys a I am doing a swap from a 3.4L to a 3.8L engine I have a 95 Camaro with a 3.4L and I just bought a wiring harness for a 3.8L but it came a from a 96 Camaro with a A4 and I have a M5 in my car. Electrical is not strong point and I would like to know what do I need to do so the 3.8L engine I have would fit in my 95 Camaro. Would I have to swap out the wiring harness from behind the dash as well and the wiring harness from the whole engine compartment? Your help would truly be appreciated.