Plus, and I can't say this enough times - I hate the idea of FSD being tied to the car and also not tied to insurance. This has always bugged me but the point is that if my car is totalled, I'll get a new car sure, but it won't be a replacement including my upgrade -- it'll be a NON-FSD car. I shouldn't have to buy it again. Considering new cars come with all the hardware or at least they should as of now, FSD should/must be tied to the account
As long as you tell your insurance company about the upgrade they should cover it if/when your car is totaled. (Of course they may raise your premium as people have reported when they added EAP to their car.) Of course normally only covering comparable retail value, so whatever value FSD adds to a comparable used car is what you would get.