As I understand it, the sensor HW got rolled out to ensure high European safety ratings. This makes the add-on a business priority for the company, and as such an important step for both current and new owners. We are all reliant on the success of the company, and it's ability to attract new customers to continue build-out of charging and keeping a great service level.
What people need, is to take a step back, remember the excitement when you ordered your configuration, and do what you intended at that time; own and drive it for the amount of time you had planned.
I guaranty you, nobody gets a fair price when the market gets more or less overloaded with used P85+, the current hype around sensors and dual engine WILL die down, and fair trade-in and used prices restored. It is still an awesome car, and will remain so for years!
And, in the end, all owners WILL miss out of something.