Have you taken a look at a Tesla car yet? From PR materials I'm led to believe that they treat their car software seriously. I doubt one can install untrusted firmware on a Tesla car; is that so?
Tesla is probably the only one I’d trust though. While I don’t expect them to be bulletproof either (at least not at first), I expect them to quickly catch on should this kind of theft appear, and make the necessary fixes. In any case I doubt they’d be stupid enough to accept arbitrary code over a diagnostics port (if they have one even). I mean, even if we forget security, why would they? Teslas update remotely via the Internet.
Your Tesla is essentially scrap after a non-minor accident, which is why most US insurers refuse to cover vehicles made by Tesla. Its as bad as rolling coal IMO, Tesla has created a massive eWaste problem. Meanwhile, rebuilding any other manufacturers car is doable, even other EVs.
Source: https://electrek.co/2018/07/31/tesla-theft-tips-help-prevent...