I recently bought a nice factory head unit from a salvage yard and the donor car happened to have the fosgate sub and amp in the trunk, so I went ahead and bought those too. My 04 spec v has the 7 speaker system with the small sub in the rear deck between the rear speakers. I already installed the factory HU and it works like a charm. Is there a way to hook up the fosgate sub and amp in my car? I also bought the pigtails that connect to the sub and amp, if that helps.