Late to the thread but been running Car Play in mine for a few years without problem. The dealer knew to switch the USB socket and wiring but being the first car they'd ever done, it took them twice as long as quoted and they spent a lot of time dealing with VW dealer technical support who resolved the issues they were having getting it to work. Only 150 cars and I imagine not all of them have it enabled meaning many dealerships won't have even encountered the issue.
Definitely, the thing that gets me is that my dealer just decides it can't be done, even brought out paperwork with a list of unsupported units and told me mine was one of them, never argued with them thought I'd just go home and do my research where I seen 2 or 3 CSS's being advertised as having carplay. Contacted a few more dealers, nobody has a clue, posted on this forum and get my answer practically straight away

new usb is being installed in a weeks time so all should be grand then
