After combing over this thread, I think I'll hold off on the JMoney pads, especially if they suppress the DT880/600's treble. It was difficult enough for me to endure the loss of high frequency extension when Beyerdynamic did away with the DT880/2003/250 design. Now the JMoney pads seem poised to take away what vestiges of high frequency performance remain of the DT880.
Also, I will note that the DT880, in any of their last three manifestations (2003/250, 2005/250 and 2005/600), have NEVER sounded overly bright, strident or piercing to me in the upper registers, apart from the odd, poor recording. It must be my ears, my listening preference. The DT880/2003/250 has better extension at both frequency extremes, IMHO, than either of their counterparts.
Arguably, though, the DT880/2005/600 is the best executed design of the bunch. : )