True or False?

False.  My components are probably reference class and expensive.   Every tweak mattered. I guess the more resolving a component the easier it is to notice a tweak 

The more revealing a system is, the more likely you will be able to hear any change when listening closely. The magnitude of the change and its positivity is subject to interpretation and exaggeration.

I have tried changes to internal vibration and isolation and the improvement depends on the piece of equipment. I find the turntable to be the most susceptible to external vibration and most improved by isolation. The amps had a more subtle improvement if any with isolation and coupling doesn't make sense because of ventilation concerns, and speakers in between with removing internal vibration by coupling it with a platform to a floor.

Anything that touches the equipment or the room acoustics can make a difference. Other hocus focus is environmental, not acousitical, and some may like that as well. It's just not an audio tweak. The degree and value is up to the listener and his budget. 

Townshend Pods under my tube integrated amp was at least as big an improvement as under the turntable. Podiums under my speakers was at least as big an improvement as under the amp. Hard to quantify these things, probably it was greater under the speakers. My turntable motor controller on the other hand responded poorly to pretty much everything I tried, until I tried springs and Pods. Both were clearly better, with Pods being the best by far. So I think it is risky saying it depends which component. It depends more which tweak. Evidence is they all respond well once you find the right tweak. 

+1 hshifi.  If you want to hear an improvement, install a Puritan PSM 156.

@rixthetrick
I've never had a crossover I've designed fail on my sorry.  When designing myself, I find the best parts I can find (within my price/budget range).  Since it would be a one off project, I'm not worried about availability later.

I was more speaking about manufacturers that have to make certain about the parts availability and the quality of the parts manufacturer. For example some Classe amps were designed with FETs that a few years later are no longer made.  you can't find the FETs to repair the amps.  So,unless you find a repair shop that stocked up on the parts before they became unobtainable, then you are screwed.

So, an equipment manufacturer can't be blind to where they are getting their parts from and whom they are getting their parts from.  There  may be better caps and resistors out there, but if there is a serious possibility that in the near future that parts supplier may not be there, then I'm looking elsewhere.

Also, as you can see on this web site.  Some people love to tweak and adjust.  They can't sit still if you paid them to.  I can't see myself  saying, wow! my system sounds great.  I wonder what the change would be if I changed  this or that.  Added padding, footers, fuses, etc.

I only ask myself this question if I feel something is wrong or missing.  Then you take the long and sometimes expensive journey into trying to find out what is wrong (component or room) and what it takes to fix it.

Don't get me started on room correction.  What a nightmare.  Get a test CD (Stereophile for example), and a sound measuring device. Run  the test in your room at listening position.  Look at the frequency response.  Gaps, holes, peaks?  now what is causing it and what does it take to fix it?
not fun.

enjoy