well some of the pros for the under car is less space issues in the dash its self, thus less modifying and what not. Cons for it are more space taken up in the cab and wiring to run not to mention the issue of the power supply and audio. The pros of the in dash is ease of setup, it is pretty much just like any double din setup, they are all ready setup to hook up to a cars preexisting harness. Another pro is that they have less wiring to worry about. A big con will be the space needed to properly ventilate and seat the unit in our cramped dash. Cost is a factor but not really all that much of a deal breaker. As for the unit I want to get, I do not really have one that I have settled on. I am more or less looking for specifics of what others have ran and the issues they had. One of my main questions is if you go with the under seat unit, (1) how do you run the power to the CPU, (2) how do you run the audio from the RCA output to the cars harness and (3) what if you want to listen to a CD or pop in a DVD?