Do you already have the sub?

For that particular sub you want an amp that gives off the most power at 1 OHM or 4 OHM, NOT 2 OHM. There is no way for that sub to become a 2 OHM sub. You can only wire it in series, which will turn it into a 4 OHM sub, or in parallel, which will turn it into a 1 OHM sub.

There are a few high powered amps that can go down to 1 OHM.

http://edesignaudio.com/category.php?type=amps
The first amp is a little too much power and a little too much in cost, but its one hell of an amp.