Do a series II swap. That is the 97-03 stuff I was talking about. Just swap over EVERYTHING (compleate engine wiring harness ect) from any 97-03 gtp and be done with it. With this you will be using the throttle body that is dependant upon a cable for movement. You will have to do nothing to the MAF. It will be bennefictial if you do some tuning to the MAF if you get a cold air intake becuase they can change the trims becuase of the Colder air. It should still run fine without it.
The maf is located in the TB of all 97-03 model 3800 engines.
Regarding the ls1 TB they were talking about- You can actually modify a LS1 TB to work on our cars. I will find the link on how to do this in a second.