Installing an ad-blocker to your car systems may:
a) prove difficult if/when they finally sort out how to protect firmware updates from unauthorised sources
b) void your vehicle warranty, because they want to find ways to stop you doing it and that's a major dis-incentive
c) result in some kind of legal action under EU legislation to prevent it
Please don't think that means I'm on their side, I'm most definitely not. I'm just playing devil's advocate.