I am looking to install the Volvo Bluetooth unit but I need some help on the parts and pieces. I have the base universal kit 31285547. This comes with a small harness but not the big thick one I have seen in other posts. Since this is for the “R” which already has the amp, subwoofer and wiring for the NAV, do I still need an additional harness? I have seen them for sale for the S60 and V70 as a separate harness around $90. The parts drawing shows a separate package with the big harness and the mute relay? My kit did not come with any documentation so any advice would be appreciated. If I can just use the base harness that came with the kit, then where do these connections go?