Well, it all depends on what you consider breaking the bank. Going off of what you have chosen for a head unit and subs, you might consider an amp of the same prestige as Alpine

Boston

and Kicker L7s

. Perhaps a JL 1000/1.You really don't wanto go cheap when it comes to powering the L7s. They want alot

. Check ebay for "class D" mono amps, I like the JL, the 1800 watt Hi Fonics, or the the new JBL amps. For a lower price, you could even go Sony. Just don't be fooled by power ratings on the heatsink, always check the RMS power ratings. For two L7s, personally I would go with one amp per sub, at LEAST 500 watts each.