How might this effect those who already have ARC equipment? I own a preamp and am waiting delivery on a power amp. Both used.

No effect. I bought my first Audio Research component in 1980 (used). I used it for an over a decade, and a friend of mine still has it and is using it… over 40 years later.

Post removed 

@jea48 fwiw, Fremer seems pretty confident in Cora. Did you read his comment at the bottom of the article that you linked?