Seconded. I know a lot of people don't like the idea of aftermarket, but you get SO much more bang for your buck. I had a Clarion CZ509 in my last car - $150 new, probably cheaper now. It plays MP3s off CDs, has AUX input, USB input for iPod or a thumb drive, and even Bluetooth A2DP and handsfree calling. It'll just work, but trying to shoehorn something into a factory setup will never really be as nice.Yes!! By swapping to an aftermarket unit! I know it's not what you want but it's probably the best option. The only other way would be to get the iPod adapter and that might not work exactly as you wish. The FM transmitter won't work great, and you loose the ability to get any info. If there is anyone with another option is SVXdc. He does sell an RCA input adapter that is available for some Subies, but that still doesn't get you your information.
Personally I would look into an aftermarket solution. I know that it won't look as good as the factory but it may be better in the long run since you would get an iPod option and you wouldn't have the issue with the CD's anymore.