When you give a monster (with monster hd) that has SR a few class levels, do those class level hd increase the SR?
Generally SR = CR + 11, with a few exceptions. I'd maintain that, when adding class levels (+1 per associated class level, +1/2 per non-associated class level). Otherwise the critter's SR quickly gets outscaled by the level of the party's casters.
Yeah that's what i thought as well but i am interested in the RAW (if it exists) as well.