In my experience, there was a difference which I could not ignore when my 2.7 had outriggers installed.
The soundstage was more expansive, taller, and deeper with layers to it. Imaging size and "shape" is more articulate. Overall, it is a tremendous wholesome improvement I hear and it gives a music reproduction... a lack of a better fitting description, "an anchor" or a strong sense of foundation to the music.
Regarding footers, I owned the GAIA 3 (or 2, I could not remember) footers previously, and it was installed with a bookshelf stand. Earlier in this forum thread, I came across a short report that GAIA took away some bass. This is true in my experience as well. However, it was a good trade-off. GAIA footers took away some "fat" in the bass, and in return, I hear more meat and bone. Bass was "cleaner", authoritative, deeper, and had plenty of rumbling articulation that fills the room it enveloped me. GAIA also gave a more thumpy mid-bass punch and a richer vocal reproduction. If you think your speakers are giving out some unwanted high-frequency sharpness or "shrillness", you may also consider GAIA footers to counter that effect. You'll end up with an almost silky smooth gentle roll-off top end, which adds to the musical "expression" for some instruments.
I have ever thought about getting the matching GAIAs with the 2.7, but I figured that the installation is not easy for a one-man operation. Hence, I tinkered with the idea of having spike plates/coasters/bases/pucks.
Am looking forward to hearing more aftermarket spike plates/coasters/bases/pucks recommendations from fellow owners here.