So if you buy a Tesla and the T&Cs prohibit you from hacking it/modding it, then you decide to hack away at it anyway, what happens if Tesla were to brick the online features of your vehicle and/or completely cancel you as a customer?

I mean the whole point is that Telsa should not be able to brick the car you purchased because you changed something in your car. Why does a car come with conditions?

Granted I may not be in the demographic for a telsa, i wouldn't ever want my car connected to the internet.

In america the current legal standard is that you go and get fucked. You do not have a right to something you have purchased anymore as long as the seller puts enough magic fine print together.