neither the 1400d or 1800d are 1ohm stable, so if you go with one of those amps you'll need two of each. a 1400d to each would be properly powering the sub, but more expensive, and the 1800d would be overpowering it. get the 1000/1, it's stable from 1.5-4ohm each so each sub will see 480-500wrms.