Ask HN: What is the most hackable car?

I am in the market for a new (used) car and a Tesla is outside my budget. I would like a hackable car that I can customize and/or integrate with other systems.

My previous car (VW CC) had fairly limited functionality of the OBD 2 and CAN-Bus interfaces. It also didn't have any radar sensors. However, it was open enough that I was able to install an android head unit that was a vast improvement to the stock experience in almost every way.

I am wondering, is there a hacker's car. Something that is relatively open and will be a good platform for hobby upgrades, and more importantly, is likely to be supported by future projects from other developers / companies in the next few years.

It seems like it may be possible that things like adaptive cruise control or self-parking could be an aftermarket reality in the not too distant future.

Maybe there are some HN car hackers that have a preferred platform?