1. If you charge for a mod, it's illegal 2. hundreds and hundreds of Megs 3. On EAW, yes. On others, it depends on how they manage mods. 4. Again, in EAW, yes....I think 5. Not that I know of, but there's probably at least one. 6. It depends on what files they use, and how dedicated you are. If you mean running at the same time, you just have to splice them to together, but that's hard and very detailed. If you mean installed, it really runs down to the modability of the game.