I had one mounted in the trunk of my talon (before the bitch rear ended and smashed it). I used a Via Epia M1000 motherboard which is a mini-itx (it's about the size of a mouse pad). It has just about everything on-board, including the processor, video card (which has tv out, meaning you can connect to just about any monitor/screen). I used a 7 inch flip out screen with built in touch screen (which is up for sale if you want), it takes up one DIN slot. I used an opus solutions 150watt power supply which is design for in car computers (I hate the term "carputer") wires straight to your car and plugs directly into a motherboard like any other psu (also up for sale). Then I just bought a stick of RAM and a hard drive. I was in the process of lookin into a dvd player, was still decideing between slot load drive which was as big as a normal desktop drive, or a slim line drive from a laptop. Once I get some my car's performance done I really want to get another in car computer. but that won't be for another year or 2. It was really nice to have a huge music library always at hand, not to mention the videos and the would-be soon to come gps navigation.

oh as for the speakers, the first thing I tried was an FM modulator but didn't like the audio quality. So I bought a new head unit (nothing too flashy), a low end pioneer, becuase with any pioneer that has the option for a cd changer (the port in back), you can buy an audio in adapter (which was like $30). You could also buy a cheap dual (aka jensen) headunit as they all come with audio in.