I have a Facelift S3 with the Tape player and 6 CD changer. I have seen a few Facelift S3's with Concert single CD head units. I thought great will get one on Ebay.... Do they actually exist? Were they a rare option? I see a lot for A4's that look identical however I am guessing they do not fit the dash hole and the Facia will not be right? Any guidance or other upgrade paths?