The Steam version is fine. You just have to use the Steam Start Menu to run things. You can freely copy the game for multiple mod installs, but you have to add them to the Steam Start and go through that. Once you are out of the Program Files folder, then it is almost just like a disk version. The Ubisoft version download I have is very similar to the Steam game in that regard also. Windows won't interfere with mod activations unless there are *.cfg file alterations, or other files that would be interpreted as "system" files. So if the mod only adds new tga image files, or maybe adds to the campaign files, then they will activate at work fine
