Can you be more specific? There are lots of amps that can make that power on 4 channels. I have used numerous Memphis 4ch amps (16-MC4.50, 16-MCA3004, 16-MCA5004, 16-MCA2004, etc...). Are you simply looking for an rms rating x4 that is equal to the MC4.125 or are you looking for a better sound...