What subwoofer hifonics 600 watt or kicker 300 watts?

[JaTT]

I am thinking of upgrading my sub I have hifonics 12" 4 ohm dual voice coil and I am powering it with hifonics Zeus amplifier at 320 RMS using all 4 channels. The bass is good it shakes rear view mirror like crazy and side mirrors too. I was thinking of buying 150 rms watt kicker 12" comp subwoofer and use 2 channels of amp to power it and use other 2 channels on my rear Sony 6.5" . Will kicker have better bass than hifonics sub? If not I will stay with hifonics. I am looking for clarity and SPL