How about expanding the ECU so that everything you've ever wanted to see/do is built in. This would include not only a vehicle manual, but also a Wifi device and an embedded web server so you can monitor the vehicle from your home computer and/or smart phone (including OBD codes, and not just the numbers but what they actually mean). Maybe even allow you to start the vehicle with your smart phone so you no longer need that keyless entry remote. Maybe view performance logs including MPGs and so on (memory is cheap). As for the security risks, keyless entry remotes suffers from the same attacks (signal replay attack) so I dont think there is really anything new here. There is so much potential here (the expansion and bringing the vehicle into an existing network) and the technology exists - someone just needs to connect the dots and implement it.