> Finally, there's the issue of privacy. Most manufacturers contract with analytics vendors to send your data back to them. You can't even turn it off.

You absolutely can. Pull the fuse of the cellular modem aka "telematics unit" or even completely remove it. Some vehicles don't have a separate fuse, in which case you will need to physically unplug the modem. Do your research and don't buy any car where this can't be done more or less painlessly.

Well thats a nice theory but do you yourself give guarantee to all models that they will keep working after such potentially destructive 'hack' ? I don't think so. Its trivial for manufacturer to make it stop working because of ie some security blah and just having a big warning on the screen to go to the repair shop.

So a typical internet advice - don't listen to it uncritically, or not at all.

Any sites which describe this across models? What else do you lose out on?