I asked the service advisor what i needed to do besides buying the remote start fob kit, and this was his reply:
Install for the remote start would be $210 (1.5 hours of labor) as it requires calling general motors for a special calibration to add remote start to the BCM and both key fobs to be programmed.
so it looks like you need to buy the fob kit, they’ll install and program, and you’ll be good!