I would rate that as "and" not "but."
Yes, that would be difficult/impossible to hack.
- can someone take control of your device (car in this case) without your knowledge or consent? This is where the access through wireless is a big concern, IMHO.
As an example, the controller for my TDI diesel motor is "hacked." It has been re-programmed for different than OE performance. The big difference here is that the change was very much under my control. The person who did the job had to physically posess the controller in order to re-program it.
In a broad sense, the firewall is a physical barrier between the computer and any means to re-program it. I have PC's that are absolutely not ever connected to the internet. No wire or wireless opportunity exists to mess them up. In that sense, I am pretty certain that they are in little danger of being infected by viruses, etc.
If a person had to physcally access the car's controller in order to reprogram it, or rewire some analog circuit, this would be under control of the owner/driver. It DEFINITELY could not be done while the owner is driving the car, which would be the ultimate scary scenario.
- E*clipse