engine swap question

00 3.4L 120K miles

I got an 00 impala coolant flooded the engine (because of the intake failing I assume) and from what I hear that job is $1200+ and alot of people i know that the car will never run the same i should just change the engine.

So im changing the engine. I found 2 different 05 engines the salvage yards say their direct fit but from what i've read the vin must have an E or whatever and the 00 impala only is a direct fit to 00-02.

My question is how can i get the 05 3.4L engine to fit. Is it a different ECU etc? The salvage yard said they can swap it for me for $450 and the engine is $650 w the the 30 day warranty. Its a newer engine so i'de rather get it instead of and 00-02.

Pretty sure the pcm programming is different, bu the interchange books used by salvage yard have all the required info as to whether and what is required for this.

the place where im buying the engine from is gonna do the job so that just makes this process a whole less complicated. if the engine is bad or it does not fit than they gotta fix it if it needs a ecu/bcm they probably have it. I just should find out if they have computers to diag the car.