Hello all, very new here first post. As the title states, Is it possible or doable or likely that a 9.3t with transmission, harness and ECU be fitted to a 2002 9-5 Arc wagon 3.0t?? Please advise, thank you very much.
I suspect that the answer is yes, if you work at it have have a full parts car to pull odds and ends (such as the throttle cable) that you would need. In practical terms, I don't see that it would make sense compared to either getting a good used 3.0 drivetrain for your Arc, or purchasing a 2.3 9-5 of your choice and specification.
It's lots of work and having teh donor close by while you do it will be helpful.
The real question will be in the electronics. The harnesses changed over the years so you should try to match up with a 2002 harness if at all possible. (what year is teh donor?)
Also you're going to have to deal with the ECU and VIN because the VIN does indicate which engine and the ECU may behave differently if it thinks the car is a V6 and it's got a 4-cylinder in it. I'm not sure how the ECU knows which engine, but if they are keying off the VIN then you're probably in trouble.
like EdT said, find a V6 and replace it, then you have none of these unknowns that may work and you'll be done in a week or may never work and you'll have to do the job again.