It is likely the 40GB download will uncompress to 104GB when installed, completely replacing the existing data. But it is not possible to know exactly how size on disk relates to content, as Larian may have modified how efficiently they store data for patch 8, in order to keep the size consistent.
They certainly have to move to a more efficient storage scheme before adding 2+ more acts at full release, or everyone will need to buy another SSD just to install BG3
Rather, it will not have more than 200gb, although I recommend reinstalling the game, it should reduce the size a bit.
I have a look my D drive disk space, and it is 237GB.
I think BG3 ought to be in 200GB, the installation will merge, update and add data into the game, but the animation video should still take many hard disk space when act 2 and act 3 add in to the game.
maybe I should prepare to buy a new hard disk when BG3 is released?
