A couple things. 10 Hz isn't really going to blow you away as a tactile sensation. It is more of a subtle effect. And there is very little content that actually has stuff in that frequency range. It's basically a handful of movies. And while the S3611 may be able to generate 10 Hz at 100+ dB, there is still the question of its audibility or sensibility. You need a huge amount of displacement for some really tangible infrasonic bass, I would guess more than a couple of 18"s with not tremendous excursion.
The threshold for sensing 10 Hz is 100 dB, and that is under laboratory conditions. Furthermore, you are wary of port noise, I get that, but a sealed system, when pushed hard, will generate a lot of distortion. And asking those two 18"s to produce 10 Hz at 100 dB is pushing them very hard. A Captivator 4000 will generate far more clean 10 Hz output than the S3611. If you push it hard enough, yes, it may generate port turbulence, but the S3611 is going to be much more limited at 10 Hz, and would produce so much distortion that its 10 Hz output would be totally swamped by distortion much sooner than the Captivator 4000 would run into chuffing. I would guess that the Captivator 4000 would have three to four times as much clean 10 Hz output then the S3611. It would be a lot more efficient in that range as well in terms of power usage.