I just read the hacker's guide. I could have written it - better.

I'm using the Arduino pro-mini (if you check out the link). Plus an accelerometer, GPS, and bluetooth. That has been running for a while. It reads all those (the GPS is 10Hz with WAAS/SBAS) the j1850 stream AND my radar detector (valentine v1).

Use parani bluetooth modules from sena.com instead of blue smirf (easier, smaller, and I think cost less).

In the image, the blackberry square is a A2DP bluetooth gateway to my docNrock. The n900 would have that built-in and have better graphics.