man.. there are just so many ways to build a car-computer I dont know where to start. look at other peoples setups and get some ideas. look up some specs and write down everything that you are looking for. if you want quiet... dont get the voompc unless you take a few fans out. (not reccomended) Those fans are LOUD.
Really man... do some searching and look at some reviews. Do you have a budget in mind? are you doing a touchscreen install? indash? the list can go on and on.