With regard to Taxes and Customs:
I specifically ordered the Digital only tier, instead of Collectors Box, even though I'd love a cloth map.
I live in The Netherlands, but this probably applies to most EU-countries.
If you order physical goods above € 22 you will be taxed for customs, administration costs AND VAT.
This is normally in the range of € 10 administration and handling + 15-30% customs and 21% VAT over total value (price of game+shipping costs+ administration+custom costs).
To be short, it can become pretty expensive.
So if Obsidian includes documents that the game costs only € 20,-- I'd probably be safe. But if a customs official does 1 google search regarding price of collectors edition of Project Eternity you'll probably get a pretty hefty tax/customs fine.