Memphis 4K has a Huge ****ed power supply in it..... bigger than the mm4000.1, but the mm4000.1 has a larger output section.... though it is divided in two channels it can be "bridged" to 1 channel, however 2 ohms would be what it would be good for "bridged".... Really depends on your sub wiring capabilities I guess.... Memphis 4K is a good amp and so is the mm4000.1. Two different amps though for sure....