Will this amp blow my subwoofer?

I have a JBL GT5 15inch it is rated 1200 watts and 300 rms and want to know if this amp http://www.sonicelectronix.com/item_17415_Sony+XM-ZZR3301.html will be able to power this subwoofer or will it blow it because of the rms. and what do you go by rms or watts when looking for a amp for your subwoofer. I have 6 gauge power wire running to it is that to weak or should I buy 4 gauge power wire and is 12 gauge speaker wire allright to wire the subwoofer