I actually like Rock music better in portd boxes. I have two 10" SW6010 Eclipse subs rated for 450rms and each are seeing 300rms on Diamond D3 600.1 and it sounds amazing!
Also if he wants good double kicks, needs to get more the front stage in order. I have Massive CK6's and they without question have some of the best midbass I have ever heard from a mid.
I like that DCON sub recommendation as well. That off 600rms amp would do real nice. Love my subs, but dont see them around too much any more.