good question....since the macmini has a cd-drive like a car cd player (no tray) it seems like you could just mount the computer somewhere accessable and use it as your cd player....but then theres still the radio. You can probably hook up a satelite radio somehow. There are a lot of other threads on car computers, just check one of them out, I'm sure they say how they get the radio to work...unless they never use the radio.

 

I personally use XM for my sat radio. XM actually released a USB version of their hardware called the XM PCR. But you can also create a serial inerface cable for the XM Direct with about 10 minutes worth of soldering work. There are a few softwares out there that will interface with the XMD. This has probably already been posted, but if you go to http://www.mp3car.com/vbulletin/ you can find almost anything you are looking for on the subject.