I have an RNS LOW which i wish to fit to my 2007 A4 B7. It's currently equipped with a Symphony unit with 6 cd built in changer with BOSE system. The car is equipped with Multi Function steering wheel and has GSM phone prep in the centre arm rest. Can somebody please advise me of what additional parts I may require to get this unit up and running. Thanks for any help, if there is any further information that you require to assist me please ask.