Well I have Rockford Fosgate 600aVI 600 watt rms 2 channel amp. It is really old but a guy at best buy was telling me that back then, they were way underated and it probly puts out way more, and it really can take a beating. So now I have to decide on the subwoofer choices. I want two 12" inch's. One choice I am looking at are the older model alpine type r's that are 300 rms 1000 peak which i can find for like $130 each. Or Infinity Kappas which are 350 watt rms, which are about the same price, except i found a pair of them used selling for only $170. Do you think i would be underpowering the kappas? if not which subs do you reccomend?