I have been running the 2200D (branded as AQ, so a few years old) on a HDC4 12" Dual 1 on a half ohm. Even though it is not a true half ohm because impedance rise and other factors, the amplifier barely gets warm to the touch. XS 3400 bat with no other electrical upgrades in a Cadillac CTS. Video from 7 months ago, still running it daily