I think the staining could happen, those inboard engines are pretty close to the fuselage and the Coanda effect would pull the exhaust plumes into the fuselage even more.
Simply stunning...the textures is spot on !
one thing: I would blur the shades cast by the wings toward the belly of the aircraft. in some ways that makes the aircraft look bigger
i see your point...it was only a suggestion that you might wanted to try out. Itīs a amazingly good job you have done with this one, so with or without blur: this is one hell of a job !