Sorry I've been busy recently and haven't been able to update y'all but I did finish in about a day, I did also do a Rolls Royce Starlight headliner so that added to the time it took me to do the mirror (because I didn't have the headliner harness in).
It isn't necessary to remove the whole headliner from the truck, however I did because I wanted to do the starlight headliner and sound deaden the roof with Killmat deadener.
I didn't have any problems, I was sure to glue the coax cable down to the headliner so it wouldn't rattle with music and also used some outdoor silicone on the bolts for the spoiler and the third brake light to reseal the cab and prevent any leaks.
Everything worked perfectly no misalignment or anything like that.
There wasn't really anyway to show you how to do it but there is a video somewhere in this forum from Infotainment.com that shows you the install, that kit is $1500 and I don't think its worth it just to have them in one box, just order them separate from gm parts suppliers, its way cheaper.
I do have a toolbox that isn't low-profile so this mirror camera system was a great upgrade.