First test run with the raspberry pi as a car computer for a gauges. On this run its a bit laggy, but I do believe there is room in configurations for speed improvements. Plus this was a visual ran through a remote desktop view, which may introduce lag. I think this was successful enough to warrant purchasing a 7" screen for it.
A short video of the test run showing the current lag. A friend of mine is pretty sure it's the remote desktop causing the lag, and the lag won't be there with an actual monitor connected. http://youtu.be/mJbFnaJXQ-Q