I loathe the idea of a subscription, but you buy a car upfront knowing what specs you're getting.
If they want to unlock more power for a one time fee, that's fair game. It actually does have a cost incurred on them via increased wear and tear and warranty claims.
But it's gotta be a 1 time purchase and is lifetime of the car.
Also tough luck if you failed to secure it properly and someone jailbreaks it. It's their car they can do whatever the fuck they want to it.