The differences brought about by isolation platforms, mains cables, etc are not subtle.

As has been mentioned, cables like the Eupen and the more expensive mains cables act like a low-pass filter, and remove a great deal of rfi junk.

Personally I'd put things in a different order to michael. In dino's system at the bake-off I thought that the £200 seismic sink made a world of difference, and was, for me, the best VFM upgrade of the day. Certainly more significant than many box changes would have been.

I used to be significantly sceptical of power cords and isolation systems and such and so forth. Now I've heard serious differences, and to that end I have a trichord powerblock, Eupens and a custom-designed rack now. Certainly that lot turned my system about significantly.

Of course, you may choose to disbelieve it and not to spend any of your money on such things. But please don't tell those of us who have heard and understand and appreciate the difference that we don't know what we're about.