The seat warmers are in all Model S in the front seats.... the cold weather package adds....
Heated Steering wheel, rear seat warmers, heated washer nozzles, heated mirrors, heated landing area for the wiper blades.
In NJ that is a nice thing to have.
You can prewarm the interior via the app but when under way, the heated seat warmers and steering wheel make for a very
comfortable interior with lower electrical usage from the traction battery. This spring I did not need to run the heater at all. The heated seat and steering wheel did the trick for me.