It’s a software switch. Either on or off. If you purchase after the FBA t it’s just in the app. In the US anyways.
As for insurance they often ask for purchase paperwork. Window sticker, etc. Purchasing after the fact is just a charge to your card with minimal paperwork.
They often look at the purchase paperwork.
Not that you can’t do after the fact but it’s more complicated. It’s like if you swap out the factory stereo with a custom $10-20K stereo system. You have to provide the issuance company with the purchase and install paperwork. They have to agree with the numbers etc. then they have to adjust your policy with an adjustment post purchase. It’s a little easier since at least both are from Tesla.
In my previous case Tesla is problematic since they asked for window sticker which is common in US. But I told
Them that Tesla doesn’t do window stickers. Ther was also nothing on my paperwork. I had to send them screenshots from my iPhone Tesla app and Tesla car screen as proof which is not something. They were used to. They are used to official, common and decades old paperwork. In the end they accepted but had to pull local comp’s which they had a hard time finding with FSD purchased and for sale used.
In the end it worked out and I got paid more than I paid. But it’s took months and I had to pay for a loaner after 30 days as they o my cover max 30 days on any policy.