Rotarius, most manufacturers do provide data on their websites - though generally not in quantifiable terms. Some Agoner's systems are so sensitive that even slipping a piece of paper under an oem footer will produce a detectable difference - if the listener has sensitive ears. There are also the suggestibility and predisposition factors. So, even if measured data was presented online it would provide very little information that could be directly applied to one's own system. That's why A/Bing in your own system is the ultimate test.
Having said that, anyone interested in learning about isolation, damping or draining of unwanted energy can visit the websites at Symposium, Silent Running, Townsend, MIB, Halcyonics...whatever...to help determine which approach might be the most effective - or pertinent - in improving the sonics of your chain. Be advised that there are many imitators in the marketplace who will attempt to play off a successful device by altering the structure or resource material in an attempt to circumvent a protected design (or to spend as little $ as possible in the mfr'ing process!). Further, I doubt that many DIY isolation devices - if any at all - will be as efficacious as those whose manufacturers have been trumpeted here on Agon. Despite claims to the contrary, you will get what you pay for with these tweaks - but you have to hear them in your system (employed in the fashion for which they were designed) before you can draw any serious conclusion.
