Yeah, but I'm not going the decent carputer route. I don't need that kind of headache. I'm going to use a small low power single board computer with an LCD display option so that I can put it pretty much anywhere, and with some power line conversion, I can power it on a 10amp circuit with amps to spare (no hard drive, display on a different circuit, etc). This solution also buys me the ability to put the unit to sleep when the car is off (< 100 mW) so it doesn't have to reboot every time. The point here is to replace my non nav display with a home brew nav display and then whatever else I can cram in there. Thanks for the pointer Jaak, I assume that one of the constant power circuits could be open, which would be perfect.