conversion

2021 Ram 1500 Laramie 4x2. I paid it off and plan to keep it until it croaks. If I can source the parts for 4x4 (after I figure out what they are), is it possible to turn the feature on using AlfaOBD? Feels like it might be a waste of time and money, but I like challenges.

I have a 2019 Ram 1500, 5.7L with 3.21 rear gears. I want to swap the gears to 3.92s. Does anyone know what other modifications would be required, if any? Computer reprogramming? Trans cooler? What exactly are the differences from factory other than the gears?