My S3 has the concert head unit, but I've always liked the RNS-E nav unit, primarily for the fact of putting music onto an SD card to save on the amount of CDs lying about, but also as it has NAV, and it looks good. Looking on ebay, they're readily available, with the GPS antenna. How much of a plug and play process is it to fit, or would it need coed to work? (i'm guessing VCDS?) Would the antenna have to go in a specific place, like up in the head lining or something, or would just being left behind the dash work? And would the phone option just start working, or is there a lot more to it that that?