The thought has occured to me to buy a MA audio MA-5082Hx, which is 1x4000@ 1 ohm(mono) or 1x2000@.5 ohm(stereo). With the amp in mind, is the Sx18 a better sub, or RE's XXX.. Also, can the RE be broken down into .5, or 1 ohm. And if so, how many watts? Thanks'