MP3's are a blessing on the computer/multimedia fanatic. I'm sure if you're able to download mp3's from the net, you should have enough sense to build your own mp3 player for your car. It's as easy as plugging in your inverter. And it's as upgradable as your budget permits. Otherwise, you'd have to pay 300 more for a bigger harddrive, and that still isn't expandable. You gotta know what you want right away, (empeg) or else if your mp3 collection grows, your space can't grow with it.