What wiring harness do I need?
 

05 B6 A4 w/bose symphony in-dash 6-disc cd changer. Looking to upgrade to a pioneer double din nav system. Can't seem to find the right wiring harness. I do NOT want to put in aftermarker speakers or subs, just looking to do wiring harness and drop in new unit.

Does anyone know which harness I need? Some come with antenna adaptors and all kinds of stuff ranging from 10 dollars to 90 dollars. Thanks