Got to work on the system upgrade today and hit some snags. All the things I was worried about were fine (XM radio-traffic-weather worked great, OnStar downloading an address while driving without issue, Rear Entertainment System functions worked great), but the backup camera isn't showing the video from the back and the nav isn't showing any action from moving (never showing progress while driving to a destination) and the position cursor stays at the origin.
It is the middle of a holiday and am confident the boys at CPS will have quick answers to fix these items, but am currently leaving it sort of done and once fixed will start the writeup. (I took pictures as I did it but will have to go back and type up notes for a separate post).
On a humor note, the XM customer service were a little puzzled that the radio ID I was giving them to swap over was not in a 2013 Chevy Avalanche as their records showed and was in my 2009 Yukon Denali. I was passed around to a few techs before I got one that understood I was playing musical chairs with OEM radios and to just make it noted that this 2013 radio was in a 2009 truck. I think he got it straight and my account looks right when I sign in via the web.