I don't know what's addressed in the FAQ and what's not at this point. I seriously need to give it a dusting and update a few things.
According to Amazon the "updated" version of
The Tomb will be released August 1st:
http://www.amazon.com/gp/product/0765355...oding=UTF8 (And at a very nice price.) This might be better for those who don't want the limited edition from Borderlands.
The only way to get the updated
Nightworld at this point in time is the limited edition from Borderlands.
There has been talk of the eventual re-release of the entire AC in it's updated "Borderlands" versions in paperback at some point in the future.
I believe there are no "drastic changes" in either volume. Not having read the updated
Nightworld though, I can't say for sure.