Honestly, the tracking is the biggest thing that would stop me from getting a Tesla. Is it possible to completely sever the data connection for the car?

"Tesla will have an enormous amount of data, of real world data, because of the millions of miles accumulated per day from our fleet of vehicles. Probably Tesla will have more real world data than any other company in the world." - Musk [0]

All things being equal, they're probably one of the best groups of people to hand this power to, but I would take an open source EV over a Tesla. Some (most?) other car companies track their new cars too (eg Jeeps broadcast GPS coordinates [0]).

[0] https://medium.com/backchannel/how-elon-musk-and-y-combinato...

[1] http://www.wired.com/2015/07/hackers-remotely-kill-jeep-high...

The tracking systems is one of the reasons I ordered a Tesla.

Google (location awareness) and T-Mobile (cellular provider) already know my locations at all times, I'm fine with Tesla collecting that data in return for software updates, Autopilot refinements, and for the vehicle returning data to them to enhance their own Autopilot algorithms.

So you don't get critical updates and your car blows up.

OR you don't get updates and your car is the only one that doesn't blow up.

Could probably route it through a non-existent proxy.

I was more thinking pulling a fuse or unplugging an antenna, but that could work too. Any idea how that would be accomplished?

Teslas connect via AT&T, so I doubt that one could add a proxy.

Find the SIM card and take it out. They might have soldered it on though.