Sorry, maybe I'm missing something, but if it's a dual 4 ohm driver, that means it's 4 ohm + 4 ohm. You have two options in which to wire that. First is in series, which will give you 8 ohm. Second is in parallel, which will give you 2 ohm.
In checking with SSA's website, the DCON specs even list the Re as 7.8 ohm which is typical when you have a dual 4 ohm driver. They provide specs based on the driver being wired in series. The specs will stay the same when wired in parallel, i.e. 2 ohm, except that Re will change to something like 1.8 ohm.