If the amp puts out 420watts@2ohms then a dual 4ohm sub wired in parrallel is best.Ok I just ordered a DVC 4ohm sub. Now I am going to order a mono amp that puts out 300x1rms @ 4ohms and 420x1rms @2ohms. What you guys are saying is that I can't wire a DVC sub to see the 300rms @ 4ohms? So with a mono amp I need to go with a SVC then? Will it not be as loud or clear, etc? Thanks alot. Oh and my sub is 350rms/650max.