AION 2 download size: current Steam Playtest depot is about 80.42 GiB download / 81.74 GiB installed, while the official Global client requires 100 GB free space.
For the Launch Scale Test, clearing at least the official 100 GB requirement is the low-risk choice. Leave additional headroom if possible because game clients can need temporary space while patching or unpacking.
The SteamDB figure is specifically for the Steam Playtest app. It should not be presented as a measured PURPLE transfer size. NC has not published a separate exact PURPLE download-size number in the current official test notice.