I can't see how many people could find a SA5000 to approach the modified K501 for percieved tonal balance for good recordings, unless they simply liked the coloration of the SA5000, which is always a possibility. I actually prefer the modified K501 over the K1000[I spent several hours with this headphone since the last time I said anything about it because I was considering to purchase], but I do prefer a K1000 over an unmodified K501. If I had not compared with the modification, I would probably have a K1000 right now. Of course, I have since found a headpone[K340] that I like more than any other for good quality jazz, classical and other acoustic type recordings.
For the user here, I would definately recommend a K1000 over the SA5000, as it[K1000] will have most of the tonal attributes of the modified K501, but it will also have a superior[to any other headphone] spatial effect that is possible only with the K1000's hinged drivers. The user made a point about the spatial effect, so I am assuming that is an important consideration for that user.
-Chris