If i have a TRU T-2.200v2 (600W x 1 @ 4 ohm) amp, would i get the SVC 8 ohm and wire them down to 4 ohms, assuming i have 2 of the peerless xxls12's?? Also on madisound, it says to be used with a passive radiator or something. What does this mean and do i need to purchase that? One last question, will 2 12's have enough output, say that equal of an idq15, in a sealed enclosure?? Thanks...