Don't even think about powering the board directly from the vehicle's PSU.
You want a 12v regulator that will output 16A or more.
You're going to have to do some searching for that. Use your strongest Google Fu.
Frankly, that EZ Buddie system is pretty high powered, making it a less-than-ideal choice for a vehicle. If you can swap any hardware for less power-hungry variants, then you might be able to use one of the Carnetix models.
I'd look into CPU and HDD swaps to lower the power draw.