2 have not been opened the other 2 and sub fitted for 6 weeks. Sound is fantastic just running from head unit, they can obviously be amped (sub has built in amp) if required. Sub uses rca (supplied) or inline speaker connections (supplied). Also supplied for free if required are speaker mounts that fit most vag based cars and speaker connectors (2). Speakers do also come with universal mounts to fit any car also. The sub has full wiring kit supplied.