Do all these different categories of add-ons co-exist together, or will some over write the other. For example, if I were to install the Blue Sphere Textures, and then install some mesh or scenery, will it cancel out the Blue Sphere Textures, or if I had add-on scenery or mesh, and then installed a Texture, will it cancel out the scenery or mesh?

Boris,Mesh, landclass, world scenery textures (upgrades) and airport add-on sceneries are all different entities that generally function independently of each other. The only thing that would cancel out the BlueSphere textures, if you were to install them, would be another texture upgrade such as the high relief textures.John

In addition, any scenery that contains custom terrain textures won't mesh well with your BlueSphere or other replacement ground textures. I can see this being a fairly big problem for scenery designers in the coming months if replacement generic textures become popular. I'm not saying the replacements are a bad thing, but they tremendously complicate matters for designers who want to use custom terrain textures in their scenery and have them blend with the surrounding terrain.

Thanks for your replies! Now I understand things a little better.