Do stands make a difference for equipment?

" Total cost, about $500. How much better can a expensive stand improve on this?
..."

Excellent question. I can only relate actual experiences and not anecdotal experiences.

When my hardware gear (amp and Cdp) went from $4K to $24K the stand and isolation tweaks eventually went from $850 to almost $5K with no other stand tweaks. The speaker cables and ICs also went from $2K to $6K also.

Did I Gulp and sweat it? - U betcha. But did it make a difference? Again U betcha... and a very noticeable improvement difference - Go figger!

Acoustic room treatments with Echo Busters became the integral matched steps. Room nodes, first order reflections, bass damping and reverberation times et al all needed attention, along with tinkering with the speaker - to - listener positions .

Can I directly parse out with near accuracy just much of the overall improvement was attributed just to the stand?

Hmmmm ... not exactly, other than to say it was not subtle. Again I was the ultimate skeptic before.

Oh, did I mention that for any of Alan's facebook friends, each Q-stand (what I use now, and will be buying more of soon) are only $350.00 each? Better hurry though, when Alan's new and only B&M store being built in Nashville comes online in the next few months, they will be a few thousand dollars each, according to Alan.

When you want a real vibration transfer, the speakers should be screwed into the stand

Not necessarily, or at least not as long as you believe in the Star Sound scientific perspective - simply bolting speaker to stand will not effectively accomplish "real vibration transfer".

Syntax,
Having tried Sorbothane padding vs. small pieces of blu-tac, I must disagree. You may prefer the Sorbothane to other interfaces between speaker and stand, but I didn't, and they certainly sound different.

Syntax,

I agree that one must not spend exuberantly to achieve positive results to damp or quell harmful vibrations; which in my opinion, negatively impact the playback of music from source components. The Schroer udn Schroer glass rack was a step up from the Saturn Spectral rack I owned before.
http://www.justhifi.de/Schroers-und-Schroers_Fly-Audio_a5080.html

I am wondering why you opted to use the Ikea wood series of platforms which you are using now versus the Copulare you owned previously? I think your new implementation of vibration control would be a great solution for a few audio geeks wanting more than just standard vibration control. Es war ok, war aber nicht mein Geschmack. It is not my taste for both; looks and vibration control.

My analysis and decision making process wa sbased on aesthetics and proven results. I tested the Copulare racks at home before I purchased them. Both my wife and I agreed on the looks and well, the sound decision was also both of ours.

Here is a brief description of the Copluare racks I own.
Each Copulare wood platform is filled with a mix of two variations of sand to further dampen the internal grids. Each of the rack assemblies are fully welded and powder coated to whatever finish a customer wants and also filled with sand. The wood platforms can also be painted to whatever color the customer wants. Each wooden platform on the rack is spiked the braced metal frame with a screw-in spike and then rests on a leather strip which sits atop the mounting area. It is a three leg and three spike per platform system. The music was simply more focused, refined, articulate, and had more authority, whereas before, I thought the music seem to have an etch, something I always fought with. In comparison, the Clearaudio MontBlanc turntable stand is such a mass loaded beast, weighing in at over 225p pounds, I never have vibrational issues with the turntable. Enough has been said here about mass and the pros and cons.

Again, my opinion is that specific mass characteristics are more beneficial than others to achieve positive results in reducing or damping vibrational issues.

To better help the OP better answer the question, it is important to know and realize that any form of vibrational control, no matter what the costs, can impart a change to the reproduced sound, both; in a positive or detrimental manner. It is that alteration in sound reproduction where the OP must make a decision if it is acceptable or not to use the specific vibration control.