Hi Rich- glad to hear you like the Europas.
Mdf stands, even with sand filling, have a "fuzzy" resonance in the particles of the wood themselves. A stethoscope would reveal this as stimulated by tones in the AM radio/nasal voice range.
If you are going to keep the stands for a while, then consider placing a thin sheet of firm rubber-gasket material from the hardware store (in the plumbing dept) between the Europa and the stand. The Europa's marble cabinet does still have resonances in that tone range, but at a much lower level than a wooden cabinet. The rubber sheet should minimize the transfer of those "marble particle" vibrations into the mdf, yet be rigid enough that the cabinet does not wiggle on bass notes (which would also blur the image). Again, a stethoscope tells you a lot.
Possibly four 3/16" balls of BluTack between speaker and stand instead would be fine, squished out with the speaker's and your body weight. But you'd find after a few weeks, the BluTack has entered the pores of the mdf- it rips out a big chunk when you try to remove the speaker. Seal the stand-top with a semi-gloss or gloss, paint/polyurethane to prevent this penetration.
Next, examine the way any cones/spikes are mounted under your stands' bases. Most cones/spikes are attached to, or simply setting under, the bottom skin of that mdf platform. Thus, the vibration in the mdf particles BETWEEN the upper and lower skins of that base will be a weak link. Bolt those cones/spikes through to the upper side of the mdf platform- with a nut on top. This clamps those two skins together, minimizing that "shear mode" vibration between the two skins. This shearing, btw, is a front-to-rear mode, so a fuzziness to the image, in the depth dimension, would not be surprising.
After all that, look at new cables- usually the interconnects from the CD player first. The rest of your gear is certainly worth keeping for a long time. This is not a slam against your existing cables- I haven't heard them. But most interconnect cables are pretty fuzzy I find. The ones which are not, I'd be happy to suggest privately.
Hope this helps!
Best regards,
Roy Johnson
Green Mountain Audio