That's going to be great when it's finished, especially with all the CAN bus integration. It makes me wish that my car wasn't an 11 year old base model of a cheap economy car!
If you're going to be putting in a Mikrotik router, they also sell the bare boards too, if that makes it easier to mount or hide somewhere.
One thing that you should keep in mind is that the version of Windows that Microsoft is releasing for the Raspberry Pi 2 isn't actually a desktop version of Windows. As far as I know, it's an Internet of Things embedded platform that you would deploy software directly to, sort of like an Arduino. That said, there are some very inexpensive and small Windows 8 PCs out there, as seen in this thread: http://www.mp3car.com/general-hardwa...ndows-pcs.html