[VX]Changing Tilesets

Quick question: If I placed something from a tileset into the game and then changed the tileset then changed the tileset, would the objects placed in game from the modified tileset change with it or stay the same? I would like to know because 5 tilesets isn't enough for my game.

I would suggest using BulletXT's SwapXT application and script. That will allow you much more freedom.