CyberChrist
You caught my attention
No - none at all, but as I said then there is not long from getting used to doing that and then forgetting where you are and changing the default xml/python files - which could easily(and fast) lead to a required reinstall of Civ4. Firaxis created the Custom folders for a reason - and that is it(I assume).V. Soma said:Cyber, but I shall have no problem if I take care and put mod folders into the,
well, mod folder under the main game folders... shall I?

OS drive considerations not withstanding then there is no real reason to place or alter anything in the main install folders instead of in the Custom ones located under Documents\My Games.