Well, I just don't think, at that price, the subs are going to do what you want. IMO, and nothing more, he would be better off with a good full range speaker and skip the sub, rather than getting so many components shoved into a box for $600. He could buy a better amp with the savings, etc. I'm just not a believer in adding more cheap components to overshadow "improve" the existing cheap components' performance. (That sounds snooty, I know.)

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire