[vv_]

> We really need the right to modify our vehicle software

We really don't and neither do the manufacturers. Unless you want frequent crashes and user-caused engine problems. Programming an Engine Control Unit (ECU) is not trivial.

> with no surprise NSA backdoor management engines

These backdoors are generally required by law (e.g. Lawful Interception for Cellular Technologies) and are highly standardized. It is very unlikely that Tesla/Apple make backdoors on purpose.