Gear change confusion

[cr250Silverado]

I have read so many posts, and messaged a few people across two forum sites; however I am still confused about a gear change on the 2014-2018 (mostly on the 2016+) trucks. I know the parts are available, and it is possible to change the physical gears. Where I can’t seem to find an answer is about reprogramming the various separate computers. 

If I understand it correctly, the available programmers can ONLY reprogram the ECM for tires and gears which only fixes the speedometer, and no one can reprogram the transmission, vvs unit, or the ebcm (abs), which is why some get the abs and brake codes after gear swaps despite reprogramming the ECM. I can’t help but believe this will also have a severe negative impact on the truck’s stabilitrak system, which I want to keep working properly. 

Is there anyone who HAS ACTUALLY swapped their gears AND reprogramed their trucks on this site? If so, what specific components (ECM, transmission, etc.) were reprogrammed? Does your truck have any error codes including the abs/brake lights/codes? What programmer was utilized for the programming?  It also appears GM changed one of their computers for 2016+ trucks so access is limited and it’s harder to get into the computer for changes?