I have (2) e12kd4 subwoofers (2003) and I am planning on placing them in a ported box. My thoughts were 4.5 cu ft. after displacement tuned @ 33 HZ. I really want these subs to pound and bump. I figure they are SQ drivers so they will hold up with the SQ reguardless. I will be pushing the subs with a Lanzar Opti500.2, bridged @ 4 ohms. (900 watts +) Lemme know what any1 thinks!!