I am in the process of getting floorstanders, actually, but I sincerely doubt that much of anything would change since I would be maintaining basic principles of bass management in a HT setup. And I am not getting them due to some belief that they'll somehow shake my walls more than the bookshelf speakers I am using right now.I look at you list of speakers you have, they are all small bookshelves. Can you fairly compare if you don't have floor standers? OP is ready to spend $1200, the speakers he's going to get is going to be very likely quite a bit better than your speakers. I won't give such a strong advice if I were you. Particular if he is willing to get used ones, he can get into higher end stuffs rather than mid-fi stuffs.
Again, the $1200 spent on bookshelf speakers would yield better-quality speakers than a $1200 pair of towers, especially if you're talking Hifi vs. Mid-fi.
I wouldn't give such strong advice when you make categorically false statements like bookshelf speakers "stop working" at 80Hz or that DSP causes distortion or room correction costs money. I'm not sure what mountain of experience you claim to sit atop that would draw you to such conclusions.
I also wouldn't get upset with someone telling you that their bass output is likely better than yours, getting defensive by saying he doesn't "know your gear", then you proceed to insult my gear. Don't be a hypocrite.