PLEASE let us know if you get the onStar working with the replacement VCIM. I don't think anyone has yet. For some reason they "can't" do it if the VCIM did not come with the vehicle from the factory. (But there's GOT to be a way)
I cant see any reason why they cant change the VIN in the replacement VCIM. If the had to replace it because of a fault then they would be able to input the VIN or am I wrong?