[slt2021]

I dont, but there are plenty indie hackers who would be happy to buy cheap $10k car and reverse engineer it.

Any backdoors would be easily detectable and preventable just by .... not connecting the car to the Internet, or folding connection to isolated VPN not accessible from the outside.

all vehicle traffic can be inspected and sinkholed with IoT firewall, if you really want it

[sodality2]

Not when cellular or satellite chips are very well hidden... You might not even know about them, let alone have the ability or knowledge on how to stop it from connecting, force it through a VPN/firewall, etc. You already can't do that with desktop PC's thanks to things like Intel ME.

[slt2021]

I would be concerned if US Space Force could not detect rogue low orbit satellites from adversaries that provide uplink to imported consumer vehicles

[sodality2]

It could use any existing commercial service. Again, you could very feasibly set it up to be plausibly deniable until it's not.