Tristan is correct. All "new" 07 radios are for warranty repair only. You can't buy them from Subaru.
I got mine from a salvage yard. Try copartfinder.com. I searched for 2007 Legacy/Outback wrecks and found one that had just been wrecked. I called them and they pulled the radio for me.
The ability to have Sirius alone was worth it to me. Having a cd player that could read mp3s was a bonus.