Actually, I think it's too late for that, at least on a tinkering-geek level.
One of my neighbors purchased a new Dodge Durango this year. Before it was a month old, it shut itself down and rebooted into safe mode. He had to take it to the dealer, where they told him that they had to reload the OS with the latest release before he could operate it normally again.
This happened twice more before the dealer allowed that it may be a hardware problem in the on-board computer, and agreed to replace the computer. It took them a week to get a new one.
No problems since, fortunately, but it highlighed to me that this has gone way beyond mere add-on black boxes and into full integration.
You may have to have an internet connection for your next car, so it can download OS updates as necessary. Of course, that leaves the door open for Autoviruses, trojans, and product spyware...
A 1970 Dodge Dart is starting to look good.