+1. I had the Volvo-accessory subwoofer added to the Premium Sound system in my 2007 V50, and it was totally and pathetically ineffectual. The Premium Sound System bass response was quite adequate by itself, and the addition of the subwoofer made no appreciable difference whatsoever in the bass response. This was dramatically evident when the Motorola add-on bluetooth phone muted the main audio system during an incoming call but not the subwoofer, which could barely be heard adding its puny subbass content. The Volvo subwoofer, at least in MY 2007, was a total waste of c. $600.