which Sub and amp: rockford fosgate 12' Marine vs Alpine Type‑X 10
 

My system is 4 rev 10s powered by 2 syn 4s, another syn 4 powering 6 kicker cabin speakers. i currently have this sub and amp in my boat:

rockford fosgate 12' Marine sub Enclosed box Power Handling 300 Watts RMS 600 Watts Max powered by a rockford fosgate 750-1D is a 750 Watt mono

or should i replace it with:

Alpine Type‑X 1043D(1st gen) Power Range: 500 - 1000 Watts in a Atrend 10-Inch Single Vented box powered with a syn4

I am happy with the RF sub and amp but since i do have the alpine sub and syn 4 why not upgrade or is it an up grade?