http://www.7elephants.com/_e/SUBWOOFERS/product/I366MD12-1207A/MD_SOUND_MD_1207_12_SUBWOOFER_2400W_PEAK_POWER_1200W_RMS.htm on a differnt web sit there cheaper
i would stick with what cj18 said stick to one amp for now, plus theres like 6 different company's that make that same sub u can find the for as low as $125 shipped so if i were u get some cheap one and play around with them...
the lvl5s will take that with ezzz... meathead is running 2 12"xl's off a ab vfl1100.1 and he plays it daily with no problems and he did have the lvl5 10s before that.