I have a smaller room than you (13x11) and have an ultra in it. Just because you have a sub that can crank out 100dB, doesn't mean you need to turn it all the way up. But a better sub is better at articulating the nuances of music and can dish out impact the way a smaller sub can't for HT.
All the subs you mention are awesome subs, it's going to come down to what you have space for, as you have a small room and some of them are very large. You think you have an idea how large they are and measure, but when the pallet shows up, it's way bigger than you ever thought it would be.
Of the ones you mention, *I* would pick the Hsu HO w/Turbo. If you can get over the appearance, there's little at $1k that compares. If space is a big issue, check out the cylinders. If it's not, take a look at the Plus/2.
They all sound great, and without demo'ing them together, you'd be hard pressed to tell the difference between them, especially in your room. So other factors are probably going to be a larger factor for you: aesthetics, size, and finish.
Good luck!