nashphil, very well. A few years ago on something of a whim, I decided to make a little study of microphone modifications, and I ended up sending microphones to Stephen Paul, Klaus Heyne and Jim Williams for them each to "do their thing" (a single U 87, a pair of KM 84s, and a pair of C 414-B ULS respectively).
Jim converted the AKGs into transformerless microphones which in the end, had 4 dB lower equivalent noise than the stock model; their high-frequency response also increased by a dB or two. The "down side" was that the mikes were far less resistant to RFI--probably because he removed one layer of screening from around the capsule in the name of increasing their "openness."
I don't accept Jim's views on "micro-overtones" or indeed, the whole notion of choosing substitute components on the basis of having a much faster rise time than should ever be needed in a low-level audio-frequency circuit. But it was evident that he knew the microphones very well. He was able to make impressive objective improvements in their performance, and beyond that, he was utterly unpretentious (I never heard a single word of self-promotional bullshit from him) and eager to take part in the whole experiment. I appreciated all that.
--best regards