Well the good thing about a BOSS is that it’s cheap. Unless of course you go insane, but you don’t need to. Ime it’s much better than any shakers because the whole “floor” moves the couch. Also being shaken by an actual sub driver, the feeling is much more consistent with real subs. The best part, is you can turn off the far field subs late at night and shake the couch in silence, save for the other speakers. I did a quasi BOSS(before i even saw the actual BOSS) in that I mounted a baffle to the bottom of my couch and installed a JBL driver from an old pb12 I had. Then I replaced the feet with the listed ISO’s. It’s eq’d by my minidsp.
For a sectional, don’t worry. If you go down to the bottom of that thread, you’ll find plenty of inspiration. It’s a real rabbit hole.
I’m not knocking other “shakers”, but my experience with them hasn’t been awesome. To be fair, that could be setup issues but they’ve never seemed like a natural extension. That’s why I went the way I did. Big room, on concrete, needed help with TR. I do have plenty of bass, but the couch thing is just sooooo effortless.
That’s my .02. It’s possible you’d love the 40 dollar ones too. But there’s not a chance on earth that they’d make your couch feel like it’s levitating.
Edit: I also did the hoverboss thing with a tube and ISO’s around the driver. Will add at least one more in the future.