In your comparison of the Kodak 400UC to Fuji 160NPC, how is it that 400 speed film has similiar if not superior grain to the 100?

I am looking for the finest of grain negative film (how I miss Ektar) (this is probably the highest factor for me b/c I plan on enlarging these negatives to mural size photos). My other factors are warmth of color and contrast, as I will be shooting mostly landscapes and architecture (old world Italy). Finally, can someone direct me to an online vendor who sells Reala in 120 rolls? does not sell Reala. Thanks