Need help getting subs to hit harder.

[Jeffdachef 5,000+ posts]

a pair of these would rock your socks. http://www.caraudio.com/forums/subwoofer-classifieds/596235-bnib-c2-audio-threatcon-2-12-d2.html

or a pair of these HDS212

or just one of this SoundQubed HDS315

 

[CrossoverOre 10+ year member]

if thats your budget then I would throw all of it at a custom box. Bandpass boxes (IMO) ****. they work great at a narrow bandwidth and only at that bandwidth.