If you are powering 1 p312d4 you need an amp that is 2 ohm stable. Neither of those amps will do, but any of the profile monoblocks would work. The HA1000m is a great budget 600 watt amp at 2 ohms. Of course the california series is more solid if you can afford it.
AP600 is a great amp, i abuse of my AP1040 i used briged @1ohm (by mistake) and on low volumen it plays for about 1 week, it just go into protect when i turn the volume up.
The CA600 is rated at 450w RMS X 1 in 4ohm bridged operation. (For stereo, that's 225 RMS X 2 at 2ohm, or 150w RMS X 2 at 4ohm
The AP600 is rated at 300w RMS X 1 in 4ohm bridged operation. (For stereo, that's 150 RMS X 2 at 2ohm, or 100w RMS X 2 at 4ohm
I own a pair of CA200 (AP400 equiv), and a CA800 (AP1200 equiv). They have all been problem free, and they work really well (Highs, Mid-bass, 15" sealed sub).