Speaker Footers and Amp stands


I'm wondering if there are 'worthwhile' advantages to placing floorstanding speakers onto stands, braces, outrigger etc, sorts of devices. sonically?

...and are amp stands always weight and type, specific or not?

Like having an amp stand for a 100lb SS amp and then using it for a 80-90lb tube amp... or is the diffs so large as to indicate another amp stand when getting another amp?

As some I've seen have a range of wieght and non-specific as to type, I'd sure hate to have to change stands out with amps too, as I am thinking about getting one.
blindjim