Ask HN: Where to begin in removing "safety" features from new cars?

Just me personally, I would start with older trucks and take it to a mod shop to get it tuned up, tricked out and not add any of the undesirable features. Not cheap but I would get the end result I wanted and the opportunity to customize anything including anti-theft toggle combo switches and make all the steering column wiring the same color. As a bonus, if it is kept looking old and beat up it is less desirable to thieves.

Try the can bus. It is often used for tge communication between components and for last resort access.