Yeah it seems the speakers are what are messed up. I'm used to overhauling audio systems in any of my cars but I'd REALLY like to leave this car alone as much as possible. I'm not even keen on replacing the factory dash unit but I'd like the ability to accept a USB key or SDHC card for MP3 files.
My guess is I'll be going the route of replacing the front speakers and running a 2 channel system plus a small sub. Whatever I can do with minimal work and modification would be best. Now to see if I can keep it all under $750 :P