Subs with room correction DSP?

I should also point out, the AM Acoustics room mode simulator is a great tool for finding the initial placements for subs, speakers and listening locations.  Try to keep all three away from the lowest room mode locations.

After that, I'd keep your Hsu and add a miniDSP rather than buy anyone's room correction, assuming you already have the measurement capabilities. It's going to be a lot cheaper.

Another tip:  If your main speakers are ported, plug them. It makes integration easier, and reduces main speaker distortion and improves it's dynamic range.

After that is all done, integrate the slopes and delay.

Next, clip any narrow bass peaks before setting the sub level. 

Set your sub to descend from it's lowest viable frequency, about 1.25 to 1.5 or 2 db/octave.  OK, now set the sub level by ear.

I believe SVS and now Hsu offer some sort of app that lets you configure the sub from your listening location.

The best are JL audio but damn, expensive. :)

I wouldn't worry too much though, setting a subwoofer right is relatively easy with any DSP correction.  Just look at the peaks, clip them, tip the frequency response generally downwards from ~ 16Hz or as low as your sub goes. 

So if you can save a couple of grand and get something else, with Room EQ wizard and a mic I'd encourage it.