Pontiac Repair: 1998 Grand Prix engine swap, grand prix gtp, boost gauge

Question
I have a 1998 Grand Prix GTP which has a 3800 supercharged engine; the engine had a minor fire and is miled out but the car is in excellent condition.  I want to install a 3100 non-supercharged engine & trans from a 2003 Grand Prix SE which has 80,000 miles .  My question is, what do I have to change over to 2003 specs to make this work. I was told the computer and fuel pump must also be changed from the 2003 car.

Answer
Hi
You'll need to swap over wire harness(es). I don't believe the pump would need to be swapped.
Engine, trans, pcm. The PCM will need to be programmed to your VIN. The year difference is great..5 years there are ALOT of differences in electronics.
The other modules MAY have different programmes in them for the S/C motor (cluster with "boost" gauge, etc...).
Not sure then if the PCM will be able to communicate with other modules.
I would think, not seeing the car, damage etc... would it  be just as easy, if not easier to just replace engine harness and damaged plastic? Again, not knowing damage and any other situation. May be an option to look into again?
Anyways, please follow back if you need more answers.
Check the PRIVATE box.
Pawl