First, let me start of by saying that I am very new to this site, the STEX, and custom content in general. I have been going through the STEX and downloading content since my game is pretty much stock. Getting the building files into the plugin folders has been easy, the tough part for me has been finding all of the dependencies...though I have managed.
I just ordered the CD/DVD set too and am not completely sure what to expect. From the sounds of it, they are completely seperate, though I don't know if there will be dependency overlap between the two since over time dependencies have gotten condensed into larger collections.
When installing buildings manually, I create individual folders for each (not sure if that slows down game load time or not).
Maybe someone with more experience with these discs can comment on their expereince.
Thanks!