You've got 800watts on tap at the moment. With this power range it doesn't get much louder for you in a pair of 12's than your current L5's. Try a bigger ported enclosure and see where that gets you. It may be all you need (and much cheaper).

I'm not a Kicker fan at all but as far as street beating goes the L5 and L7 properly powered in a big ported box is hard to beat for the price and performance.

 

we just did a big system the other day with hertz 6 x9's , high energy components, hertz subs and Phoenex gold amp for the subs...the speakers and subs far exceeded my expectations! very nice sounding...subs were very loud as well