I'm sure I can use the 2.7 wiring harness, and the ecm on the 3.2/3.5, but I'm not 100% sure.

Thanks.

 

No the wire harness is not the same.

 

if he leaves the wiring harness on the 3.5 oe 3.2 then it is plug and play if the years are 98-01 or 02-04. If you take the 03 and try to use it in a 99 thenthey are not plug and play.so a 98-01 2.7 and 3.2 are the same connections and the 02-04 2.7 and 3.5 are the same connections. Yes the ecms will work just fine.