ok, first off, that amp will not work very well with thoise subs as they are 4 ohms each and the amp will only bridge to 4 ohms or only output about 90W to each sub in the 2-channel mode. You will want to look at getting an amp that is capable of bridging to a 2-ohm load for those woofers. Most people willnot recommend RF woofers, especially the lower lines of their. I second the opinion of going with 1 12" sub in a nice sealed box and then getting a decent 1-channel amp to drive it. I am running one ED12k.44 and it is plenty in my P5, trust me.
1 REsonant Engineering SC12 $169 plus shipping from respl.com
1 JBL bP600.1 or bP1200.1 $193 shipped, $240 shipped, respectively on ebay
My suggestion