I want to run 2 12" Fi Bls on a Sundown 2500.1, i should order the subs as dual 1 correct? Also, what is the weight of a Fi bl 12"

That is correct, if i remember correctly around 30 or 40 lbs.

When both of my fi bl 12's came in the mail package said 52lbs but that included the wood and the card board around 40-45lbs for the sub it self Heavy little sucker. Dual 1ohm if you plan to wire them at 1ohm to get most power out of your amp or what eva ohm you want to hook them up at then see if you need 2ohm. Wish i ordered mine dual 2ohm to run them at .50 ohm load but its skraight not a problem they make my head spin so thats plenty