I built my MK4 with a power amp in the trunk and an input jack on the console so I could play the MP3 files on my cell phone. That hasn't turned out to be very useful, until now. I abandoned the jack on the console and installed a 12V Bluetooth adapter on the amp. Then I found a text to MP3 converter on the Internet and made a description of my car. Now when people walk up to the car I play them this file:
https://drive.google.com/open?id=0B-...WppLUZwa2Nrb3c
or this file:
https://drive.google.com/open?id=0B-...FFOWXlVcVg2UmM
Great for car shows and gas stations.
Brian