It is correct that the BCM's are locked with one little exception that I know of involving the remote start. When you buy the kit from GM it comes with a code or someother electronic way of unlocking just that option on the bcm and only one one car per kit.
So buying the kit from the dealer and having them program it will work flawlessly, but to do it without the dealer we would have to get around the bcm unlocking issue and all.
The bcms are the same part number and just the programming within them has changed. I forget what the kit itself costs from the dealer.
If you have the plus sign on the back of your remotes you already have the long range antenna or remote reciever installed.
