I'm powering the K1000s with an Emotiva RPA-2 using a GS-1 as a pre. I few members heard it at the recent NorCal meet.
May be moving shortly into a place with my girlfriend and was going to downsize the rig. The K1K seemed the least practical, but when trying to go back to the HD580s and RS1s recently as main dynamic cans, damn everything seemed so bland.