The factory told you that 16 Ohms was the same as 8 Ohms? They must have known it was you, Mike.
FWIW, I spoke to Bob Polley on the phone, and asked him to bring my old speakers up to current spec last Easter (2007), while they were in for a service. I asked him about any available upgrades, and effectively gave him a free hand with my speakers, money no object.
But whether or not the Mid driver has changed in the last few months, is completely beside the point. The Gearslutz thread is from 2003 or 2004 (can't remember which).
The point is that two people here "spouting off", so to speak, are claiming they can hear distortion, whereas the rest of the world seemingly does not have that problem.