Hi, Im going to install my Sony HCB-700 into my Astra MK5 today, and want it to plug directly into the car speakers for audio, and want it to mute the radio when I get a call.. I have been told I need both of these cables...

Hi guys, I am hoping to install a Sony HCB-700 hands free kit to my 2008 Astra next week, although have been advised to buy a wiring harness.. What is the benefit of using this harness, and which harness will I need? Also, if anybody has any hints or tips for installing this handsfree kit, I...