When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The Dension 500S BT is what you need. Search the forums for info on it as it's not a perfect solution, but it's your best bet beside replacing the PCM with a modern unit.
Just installed on my 2008 TT with Bose and the sound from the Dension is fantastic; however, BT Audio has been a problem (for music, phone is great). Most of the time I have to connect to USB port for music.