I've got a hifonics xxv 3200$375
Also my personal favorite amp, autotek mm3000 for $450
Both amps put out rated power and then some. People have seen over 4k rms out of the autotek. As for efficiency, not sure about the hifonics since i didn't get much play time with it. With the autotek, i had 2 optima's and a 150amp alt powering my 18 ssx. Power never dropped under 12.5 even when playing a complete bass track. Bass race 144db and still at 13+ volts
*Add shipping from 90713 and pp fee