C4S offers a higher specification "sound package" audio system, featuring a single-CD slot (and provision for a CD changer) that is accessed by flipping out the head unit. CDs can be stored in Porsche's familiar CD storage system, which accommodates four CDs and is mounted directly beneath the sound system. The unit features 10 push-button station presets, an LCD display panel, volume knob on the left, seek knob on the right, plus Bose speakers in the front doors, dash, behind the rear seats and beside the rear passengers. Numbering a total of eight speakers, including sub-woofers, the system's sound quality is exceptional. The aerial is integrated into the rear windscreen.