The 2.0.x to 3.0.x convertor will not change anything with the style on the 3.0.x board. It will, however, use the permissions from the 2.0.x board overwriting the 3.0.x permissions. I don't know what you mean by titles and descriptions, but I imagine those will be overwritten also. I don't know of any way to avoid this.
Have you hugged someone today?