$9K. Reasoning for the upgrade that I swore I'd never need:
The original plan was for the S60 to just be my "around town" car and to replace my wifes midsize SUV (which was our travel car) with an X next summer. However, after a test drive, she decided the X was just too big for her. So that threw a wrench in my plan. We've also discovery that my S is much more comfortable to travel in than her SUV and between the trunk and the "frunk", actually has more storage. She's also completely fallen in love with the model 3. The final twist was Elon mentioning the v3 superchargers. I'm assuming that only the new battery tech they'll be introducing with the model 3 will be compatible.
Sooo... now our plan is to get her a Model 3 and we'll replace my S60 (now a 75) with an X100D (or whatever is top-end but not P at the time) once the X has the battery tech that allows for the very quick supercharger charging. That leaves us with my S as the travel car for a probably 2-3 years. The 60kw battery technically could have technically taken us everywhere we'd ever travel but a few legs between superchargers would have required us to travel at 80-90% speed, etc. The little bit of extra battery capacity with the upgrade should allow us to travel anywhere we want without having to drive slower.
That's also why I now want AP (for TACC) but can't get it...