Isolation footers for amps

I'm looking for advice/recommendations for isolation footers for my amp -- an Audio Research D300 (solid state). Currently I have it mounted on a free-standing 4" thick maple block, with spiked-tipped brass footers anchoring the base to the carpet on top of a basement (cement) floor. Would I obtain any additional sonic benefits by placing after-market isolation devices between the amp and the maple stand? I should add here that I'm not looking to spend a great deal of money on this... something more in the range of $100-200. Options in roughly that range I've found on line include Audio Prism Isobearings, Herbie's Tender Footers, and Mapleshape's brass footers. My (perhaps imperfect) understanding is that the first two are meant to isolate a component from vibrations in the room (including those from other components), while the third is supposed to help 'drain" vibrations from the component in question itself, thereby minimizing their transference to the audio chain..

I'd welcome advice from fellow Audiogoners more experienced than I on the extent to which these devices confer audible sonic improvements and, if so, which ones they'd recommend. Thanks

I’m giving serious consideration to yanking the magnetic suspension out of a 2017 Mustang GT350R and seeing what that baby will do. Yeah!
Herbies's Tall Stiff Tenderfeet.  Very neutral effect across the frequency spectrum.  Softer footers sucked the life out of bass impact.  Ugh.
I use Stillpoints with Symposium shelves under my amps. Unfortunately I need two sets of each since I am using mono's. Sounds very good but expensive.

I've used many Herbie's products but didn't get the results that would make me endorse or recommend them. In almost all cases they did nothing to improve sonics and maybe made things worse. I know they have a dedicated fan base, but I don't give my money to some one just cause he's a "nice guy", there needs to be results as well.There may be a lot of "expectation bias" among buyers at work here, if you believe in that stuff. IMO buyers are better to save up for the higher level stuff. Where's the beef?

I was blown away on first hearing Sort Kones and Stillpoints. Definite improvement over stock feet. Different models of each give different results, but even the cheaper ones do what most other other isolation products do not, adding more solidity, impact and resolution to the music. The Symposiums look interesting as well but have not heard them.
I still have several sets of Herbie's Tenderfeet and, Herbie's Tall Stiff Tenderfeet. These were the last tweak I was using under the Integrated amp, Transport, and Dac.
At geoffkait's advice, I switched over to the Super DH Cones from Golden Sound. Wow, huge positive difference.
I'm not knocking the Tenderfeet, @dill (above 6/14) might have said it correctly. My two systems are as follows:
#1 Rack sits on carpet, on a wooden stage, on concrete.
#2 Rack sits on carpet on concrete.