amp/sub combo

Well here are the two options you will have with your dual 4 ohm subs...

OR

You will not be able to achieve the most common 2 ohm setup that most class D sub amps are optimnized for. However a nice two channel amp that is bridgeable will you suit you well. I might add that the audiobahn amp you have chosen will not produce the listed power, so steer very clear of that brand, please.

Well an alternative to the a-bahn amps that some people have good luck  with are the hifonics amps, I personally have never had any experience with them, but what I have heard, they work well. JBL also has a good rep for producing a good over all amp at a very reasonable price.

How about a budget?

Well typically most mono class D amps are optimized to produce the most power at 2 ohms. Like this one and this one.

So in your situation your best bet is to get a solid 2 channel amp, like this one or this one, however I cannot attest to the US acoustic ratings but my guess is that they are more honest than the a-bomb ratings.

But you must not rule out a mono amp either, thye still will produce plenty of power at 4 ohms, and there may be a few out there that are cheaper and more powerful than a 2 channle amp, like this.

Just remember I have nothing to gain from recommending you to a better amp, just a better piece of mind.