Have you tried changing the bump/displacement settings? The two renderers deal with those differently IRC. Also doesn't FF default texture filter and post process blur filter for smoothing? My /guess/ is you have a noisy displacement set too high and the sharper P4 render is just revealing that... I often see this "pebbly" skin on peoples African or African-American characters for some reason... I belive there is a DAZ V4 character called Nikko or something that has such skin in the promos.

Does anyone have a link dirrect to Bagginsbills procedural "pore" pdisplacement?

I think all skin benefits in P4 and FF renders from face-off's Real Skin Shader or one of its newer varrients.. the scripts can be adapted to any character. IRC it sets the displacement as well as doing Fresnal and all sorts of other fancy shader stuff.