My Lilly pie (U2) is quiet most of the time, but she hates to be left alone....she also became furious, (very noisy is what I really mean) when I had to bring an eclectus in the house for a couple of hours before my friend picked him up. I would love to have another bird, but why try to fix something thats not broken? My home is very balanced right now with the pets we currently have and I have seen some tempting ads for birds around here, but, thank you, but no thank you.
If I were you, I would try to see if a friend has a bird or someone would maybe let you try it out and see how your grey reacts to another bird. There is no species of parrot that is compatible with another, it all depends on each individual bird. My Lilly lived with a double yellow head amazon (even in the same cage) for years before I got her, but she hated while that eclectus was in our home.
good luck.