Briefly, what's been mod'ed on your MkIII's. - Caps etc, or has the input circuit been changed entirely and the circuit board swapped out. Years ago I got some boards from Purist Audio Design, the guy who later went on to sell water jacketed cables, etc who I believe still sells some cable stuff, and mod'ed a pair of MkIII's. They were good but not as good as a stock Citation II.