I'm with Tom. Although I love to tinker and I can overspend on gadgetry if given a loose leash, luckily the term "law of diminishing returns" kicks in to my brain at some point to save me from major trauma.

I'm Extremely happy with my sound at this time without room treatments (other than the strategic placement of furniture & decor)and with just basic calibration. I continue to tinker but more so just for the sake of tinkering. Someday, I want to do something to smooth out my serious bass nulls as this is a very noticable problem and probably worth the time and energy for me. However, I don't feel the need to invest thousands (or risk my marraige) over very tiny, incrimental gains.

In my personal opinion, since you asked, dropping speakers into the floor would be going a bit overboard on the diminsihing returns scale and actually likely drive you downwards in sound quality a bit vs. up.
With great power comes Awesome irresponsibility.