Moin people, in my Opel Vectra I wanted to install a subwoofer with power stage and wanted to ask if a cable with a cross-section of 6mm2 is sufficient as a plus line? Power stage: http://www.amazon.de/…/B000UL2Q2Y Subwoofer: http://www.amazon.de/…/B000UL2HMS Cable: www.reichelt.de/index.html?… At the power stage I also only connected the subwoofer, the speakers I still have directly on the radio. mfg