I have a 2004 b6 a4 avant with the concert system. Now i am wanting to change to this headunit http://www.halfords.com/webapp/wcs/..._productId_772567_langId_-1_categoryId_165474 however i am unsure as to which cables i am going to need. I guess i will need an adaptor but i am not sure which one and threre are so many around. I have seen an aerial adaptor also which seems to need an ignition live? This is my first audi, i have done swaps on fords, citroens etc with none of this hassle. Could someone advise me as to what i am going to need. My list so far is: 1. The new headunit 2. the single din fascia surround Any help greatly appretiated. Thanks Will.