xekushnr wrote:if you want to make it work, you will need an amp, an EQ, some RCAs, an 1/8" stereo jack, and some speaker wire. if you have to buy the amp or the EQ, it would be cheaper just to buy a headunit with an auxillary jack. sorry.
Actually, when you really think about it, it would be better to buy a head unit in the $120-$150 range *new* that can read MP3 files on a CD. If you aren't afraid of refurb, you can get some good deals on Ebay. I'd skip trying to make the shuffle work and just watch for a good deal on a head unit. I think the Pioneer stuff might be nearing the end of its product cycle, so you should be able to find some good deals, even at a brick and mortar store.
I just got a Pioneer DEH-P3700MP. It reads MP3 and WMA files, and with a $140 adapter it can interface with any iPod with a dock connector (iPod Mini, click wheel iPod, iPod Photo, etc.)
You can burn a ton of MP3s on to a CD, and a good head unit will actually read the ID3 tags so you know what you're listening to. Also, you'll be able to control the songs via the headunit instead of messing around with the controls (and lack of display) on the Shuffle.
I have a Shuffle, and to be honest, I don't see much advantage to it in car audio use. It doesn't hold much, it has no display, it would be awkward to control, etc.