since your subs are dual 4 ohm, you cant wire them to 2 ohms. its just how the ohm law works, if you want to wire to the lowest ohm possible on those subs, which is 1 ohm, getting an amp thats 1 ohm stable is the only way, and i would reccomend a monoblock amp if you wanted to get another one, which is a single channel just for subwoofers