I replaced with 2 x 450W RMS bridged 8ohms AMPs.
These are from Jaycar in Australia and no longer available. I paid $280 each. But yes the A800 is a great buy for Sub applications for the price.
Power output: 2 x 200W RMS @ 4ohms, 2 x 150W @ 8 ohms and 450W RMS bridged @ 8 ohms
THD+N: <0.1% 20Hz-20KHz
Voltage Gain: 39.8dB into 8ohms @ 0.775V
Switchable input gain: 0.775V, 1.0V, 1.4V
Input Impedance: 20K balance/10K unbalanced
I replaced the stock fans with much quieter 2000RPM fans.