Any tweaks recommded for under cd player?

Pick any three mentioned thus far and try them.

As you can see, there is seldom a consensus recommendation when it comes to tweaks.

Oh yeah, I'll add Grand Prix Audio Apex footers...

I've got my Meridian on a Neuance shelf (neuanceaudio.com), on top of some small Michell tenderfeet (available all over). Didn't try anything else before this setup in terms of isoloation, but realy pleased with how this combo works. Can't speak to what it may have done for extension, but the improvement in focus and pacing was palpable.

Any one tried the marigo labs mystery feet?

Over the years I've tried BDR Cones [didn't like either flavor], Blue Circle cones, Mapleshade brass cones, but liked the Neuance Shelf the best.

I use the BDR cones on a shelf directly below my CDP 7TL MkIII. I have the cones screwed directly into the threaded holes in the gold feet where Lector's own small cones can be threaded. No vibration issues whatsoever. Other things that may affect/improve the high frequencies include changing tubes, changing IC's, and CD treatments and mats.