obd2 magnum swap?

ok im diving into the wiring and I thought I had a harness from a 96 I was wrong. I found the part number of the harness and ecm and called guy I know at dodge dealer. they are both from a 2000 Durango. however im missing the grey connector on the ecm. the grey connector and fuse box are both part of a body harness. surely guys aren't installing the entire body harness. what did you guys do? what would you do differently? the fuse box I have is the small one, none of the wires from the engine harness match up to the fuse box, I would have to repin the fuse box, or use the bigger fuse box. what would you do? im really trying to not spend $900 on a hotwire setup. thanks