There is a new product out there that has some great possibilities for carputers.
It is called the DashHawk
If the interest is here, I will try to get him over here to monitor any of your questions.
The initial version is only set up to view logs on your pc. There is software in developement to display realtime data on the PC, with a good possibility to access specific data points (mph, rpm, oil pressure, etc) to use with different apps/skins.
Updates to the DashHawk are done via USB.
Check it out!!