Look OP,
Don't get a **** audioque. they are over-rated and over-priced power hogs and more money and power than you need.
Look at something similar to those hifonics I showed you.
You are looking for a single amp to push 1200-1800 watts at 1 ohm.
At that level with the single amp you shouldn't need any major upgrades. The Big 3 is allways a good upgrade, even if you have no aftermarket electrical systems in your car, so do that.
Finally if your subs share the same airspace, running 2 amps to power them instead of 1 is stupid for a multitude of reasons.
First it will ruin your subs because the separate amps will never push exactly the same signal causing pressure differences inside the box between the subs, which can easily damage your subs.