Will the wiring harness that connects to the starter, alternator, high side pressure sensor, ac clutch etc., be interchangeable from a 2008 2.3L manual to a 2008 3.0L manual?

I assume that they would be interchangeable.

 

I don't see any reason why not
Are the starter motors on the same side of the engine?
3.0l is on drivers side
Not sure on the 2.3l Duratec engines
2.3l Limas were on passenger side