I think computer would be the last of my conserns.
At first, I'd think you would need all the wiring of the shifter and the center console to fit from a car that has the shift tronic.
then after you need the tranny and all linkage and sensors and what is needed to fit it with your 3.4.
Then maybe at the end I'd think about computer programming, but I would have been through so much trouble for the rest that I would have abandonned the project
It would probly cost less to fit a manual tranny than to try and fit that kind of tranny and from what Ive seen, it cost a lot to swap for a manual.