You donīt need any internet connection to play SH5, only when you install the sim to validate your Key that comes with your DVD.
Ubi change sh5 DRM some time ago, also the price has dropped a lot in the last months, iīve buy it for 4 $
And finally itīs a must have the original game with the original Exe file because you can fix bugs impossible to fix with non official files like others that can be downloaded in some pages.
http://www.subsim.com/radioroom/show...ight=bug+fixes