Her is how the sub needs to be wired correctly to get the sub to your final 2 ohm load. Im sure the diagram isnt the best when it comes to having direct leads verse having spring or screw down terminals. I know the box is heavy, believe me I have my share. I know it blows azz but you are going to have to do it. Gets some help if need be.
Get an Electrical Home Red Twist Red cap/Butt, and a small roll of Electrical tape, and one or two 4-? zip ties work great.(you can find these at H.Depot/Lows or even at an Auto Store/Even Walmart man.
Take One Poss wire from one coil and one Negative wire from the other coil and strip approx 1/2" of the jacket off the leads to expose wiring so that you can take and twist together to the RIGHT. As tight as you can by hand as one, Then you take that Red Home Electrical twist cap/Butt and twist to the RIGHT as tight as you can on those wire. They are together as one wire now.Take a Zip Tie and zip tie these together just below the Red Butt as tight as you can(You can do two if you like, then tape the piss out of the wires and that Red butt to cover the gap.(This way the wiring doesnt come loose inside the enclosure )Done deal. The other Poss from one coil and the other Negative from the other coil go to the amplifier on Pos and Neg as it is. You can check the wires with a DMM before attaching to the amplifier to see if you are within the limitations of the 2ohm load. I would do this before dropping the sub back into the enclosure. I would also look inside to see if all the corners are sealed inside of the enclosure. If not.. Id get a tube of silicone and do the entire corners of the enclosure and leave the sub out on top of the box and let some air in to dry quicker over night. Put the sub back in, and make sure its going to seal around the hole so no air is released and screw it back in.Put it back in the vehicle, Wire Poss to Poss and Neg to Neg on the amp, and turn all your settings back down on the amplifier. Then place your setting back on the HU and try the setting on the amplifier as Bobby has stated since he knows that amp and I have no introduction with that amp series.