Wow, I haven't been on this board in months. I just finished my mp3car project not too long ago, I will get some pics of it up soon. I love this stuff. Seeing so many other ppl really into it is great. I heard someone mention a need for a 250w dc-dc atx psu. Here is the one I'm using:
http://home.pacbell.net/plasmadi/dcdcpsucloseup.jpg
http://home.pacbell.net/plasmadi/dcdcpsuback.jpg
This thing is awesome. However, it did set me back around $200. I figured it was worth it, seeing the trouble I've seen some ppl go through trying to use inverters, or make their own psu.
plasmadis