Interesting about your MDA 300 problem. I evaluated the KSA-150, KSA-250, MDA-300, and FPB-600 on Thiel CS 3.6 and found the MDA-300 combo to give the smoothest, mellowest balance, and the most potent bass. Soundstage was a bit forward and very wide, but not as deep as the others. Note that this was with the stock power cords. When I substituted Synergistic Research AC Master Couplers (recommended by The Cable Company, with over 300 hours of break-in), the sound of the MDA-300s got a lot worse--glary mids, weaker bass, little depth. The KSA-150 and -250 sounded a bit distant (laid back?) with a recessed midrange.