Hi, I have a 2004 A3 with the standard Concert head unit. I have found a website, when looking for a wiring harness, that is presenting me with about 5 different ones. What one do i need for my car? I read somewhere that i may need to cut wires?! Is there just one harness i can get to plug into the wires that will then go into an after market head unit to be used with the standard speakers? I dont have the Boss system. Thanks, James.