Hi! I am currently sorting my CD / music library. Being a bit of a collector, I gathered over the years many, many different versions of the same pieces and concerts. And I now realize that I should not have done that .... whereas I do enjoy the different interpretations, I seem "not musically enough" to really identify differences which warrant separate purchases. However, what I do notice is the big variety in sound quality, and my HD800S is rather merciless in showing them. In terms of all the equipment discussed here on head-fi, I kind of conclude that one of the biggest upgrades one can do is ... to replace older recordings before the mid-90s with more current ones. Do you share these opinions?