For those that want to know a little more about the difference between a "heat pump" vs on "heat pump" this professor, who I believe is no longer with is, goes into detail about how these systems work. It happens to be the Tesla's system:
I challenge anyone to watch this video and tell me adding this to a vehicle as new ISN'T a major change that would rival the engineering difference between most traditional manufacture's model year changes. This is a fundamental design change. Again, we are talking about one set of vehicles never having it, then a break in the assembly line and all vehicles from that point have it...