Hi JD,
Most of your observed improvements are consistent with a lowering of the noise floor. Perhaps it was the noise floor of the brain's circuitry that was lowered (not the noise floor of the electronic equipment). If you think about it, the brain has to process and deal with the subtle vibrations in your body while it deals with the musical sound waves at the same time. If you reduce the extraneous vibrations on the body, more of the brain's resources are available to process the music. Based on other experience, it makes sense: When we are more rested, our cognitive abilities are sharper and the music is more enjoyable. On the other hand, when there are distractions, our attention is divided. IMHO lowering the noise floor of the brain is another frontier for audiophiles to pursue.
Best Regards,
John