Im purchasing 1 fi btl n2 18 inch, and im not sure whether to choose dual 1 ohm or dual 2 ohm. I have a 4000 watt mono amp with a lowest possible rating of 1 ohm. I used to have 2 12s but im moving to this 1 18 inch and wish to have it running at 1 ohm. Ive read around and from what ive heard, i should go with the dual 2 ohm sub, but i wanted to be sure before this purchase. thanks for your help