Pioneer 4-Channel Class D Amplifier Black GM-DX874 - Best Buy
Kenwood eXcelon X302-4 Class D 4 Channel Power Amplifier : Amazon.co.uk: Electronics & Photo
In Phase IPA9704D 2 Ohm Stable 1600W Digital 4 Channel Car Amplifier | Halfords UK
Juice Car Audio JA1504 1500W 4-Channel Bridgeable Car Power Amplifier, Thermal Protection, RCS Output, Bass Boost, Class A-B : Amazon.co.uk: Electronics & Photo
Wavtech Ultra-Compact 500W 4-Channel Amplifier with OEM Integration
JBL STAGE A6004 - 4 Channel Car Amplifier 60W RMS x 4 @ 4 Ohm | eBay