Alpine Dynaudio 100W RMSX4 4 Ohms 4 Channel Amplifier Volvo C70 | eBay
The amp has screw terminals (is this a thing now?) just like a normal amplifier except it has a DIN plug for the RCAs and remote turn-on. It says 100 watts x 4 and a fixed 20Hz subsonic filter so it's set up for full range. It looks well-built and it's made in Korea.
Do OEM amps have to go through a tougher quality check since it's built to last alongside with the car? This could be a sleeper if it lives up to the name.