I would preferably like to trade my factory radio out of my '05 STI for one that has the auxilary input. Or if possible just buy the auxilary input although I am not sure that it will work with my radio. If there is no interest in a trade I may be willing to just buy one from someone for the right price.
To help your search, you are looking for an 07 6-disc stereo with the aux input (2 separate parts). The wrx and sti radios are the same for 07. They are both backlit green. An 08+ stereo probably won't work without modification (they are wider). An easier to find (and likely cheaper) alternative is to use the jazzy engineering (or similar) aux input on your stock stereo.
^^ He beat me to it!! Have you heard about this? We have a few people here actually have it and they seem to like it. http://www.jazzyengineering.com GL
Long shot, but I have my old 07 stock head unit + aux port for sale on here. The CD isn't working at the moment, but I've heard from dealers that it can be sent in and repaired quite cheaply.