I'd like to replace my standard head unit with an MP3 compatible unit (aftermarket) because the dealers want to charge an arm and a leg for the standard MP3 compatible unit...anyone know what the easiest way to do this is? Of course I want it to work with the standard stalk controls (so that I can adjust the volume, change tracks, etc). I don't have an iPod (and I don't want to buy one) - are there any radios that will work out of the box without having to buy any kind of interfaces?