Your question was specific to CDPs, but I did have an opportunity to compare a Counterpoint SA220 amp, modified to a Premium NP220 by Mike Elliott, to the stock SA220. I owned both at the same time, and was able to A/B compare the two. The modded amp was a significant and noticeable improvement over the stock amp in all aspects.
But, that being said, I tend to agree that there may be a lot of "rationalization" when one pays big bucks for a mod.
But, that being said, I tend to agree that there may be a lot of "rationalization" when one pays big bucks for a mod.