Amp wants a 4 ohm bridged load: so that is either two 8ohm SVC subs wired in parallel - OR two 4 ohm DVC subs (voice coils in series, subs in parallel). Couldn't find a ratting on the amps bridge output, but I'm guessing around 300-450 watts. So figure 1/2 that for each speaker, so you'll need a pretty efficient sub if you've got a sealed box.
If the box is sealed then I've had good results with Kicker Comps, MTX Thunders and Polk MMs. Currently running a Polk 12" in my car now and really like it. Got a Kicker L5 in my truck but like the Polk more (smoother, better SQ).
My equipment list is here. Playstation Network ID = jmii ...that's JM roman numeral 2