You know, I'm not normally much of a believer in burning in earphones, but I did notice a change in the sound of my CKM's the more I listened to them. The high end does get more relaxed as they break in and lose their harshness and sibilance. Instead of constant noise, I'd put an iPod set on shuffle to the different kinds of music you listen to, and crank the volume up to just about the loudest level you'd ever listen at, then just leave them for a solid two or three days.
experiencing and performing the same thing with my Sunrise Xcited now and it's been 20 hours and hoping the treble relaxes even more with further burning.
i guess this is universal for all dynamic iems. :)