Pioneer GM-DX874 1,200 Watts Class D Powerhouse Amplifier, 4-Channel Amp, Variable Low-Pass Filter, Compact Design, and Remote Bass Boost Control

Pioneer 4-channel Two channels for your two 80W speakers, then bridge the other two channels together to push your one 400W subwoofer. If you decide to upgrade in the future, you can use that whole 4-channel on your door speakers and just buy a separate monoblock subwoofer amplifier. Use quality wire.