Amazon.com: DS18 CANDY-X4B Amplifier in Black - Class D, 4 Channels, 1600 Watts Max, Digital, 2/4 Ohm - Don't Sacrifice Space for Power - Compact Mini Ampflier for Speakers in Car Audio System : Electronics
AudioControl D-4.800 D Series 4-channel car amplifier with digital signal processing — 125 watts x 4 at Crutchfield
Amazon.com: Timpano Compact 4 Channel Amplifier Car Audio 500 Watt, 4 x 125 Watts at 2 Ohms, Mini Stereo 12 volts Full Range Class D Amp, Bridgeable Amplifier 4 Channels TPT-500.4 : Electronics