And don't worry about regions. PC games (all computer software, I believe) are not region coded/locked like console games.
Sadly, that is not correct. This is particularly true when Steam is involved. Steam has the ability to block access to certain versions (or all versions) of any game based on your IP address.
This is usually used for retail copies of Valve games (e.g., Left for Dead 2) sold in Russia, Hong Kong, etc., and for some games sold over Steam in Russia (e.g., Max Payne 3).
GFWL is also not exempt from this, Dead Rising 2 Off The Record, cannot be installed or updated from German IP addresses.
At least, in the case of Dark Souls, there does not appear to be any regional locks either through Steam or GFWL.