Well done. That`s a lot of sketches. I like your fluidity in style and the way you master pencil.I see influence of Birdcage concept in the rear, also the concept reminds me of some Oldsmobile Aerotech concepts from 80ies. maybe you could fine tune some areas. Like the lower part of rear bumper. Maybe it could go down a bit otherwise we can see half diameter of the wheel from rear prospective. It would distort its proportion with the front overhang, then you should follow the influence on that too. Also the roofline seems to curve almost all over the body, it could be, maybe shortened a bit. Also it is interesting to note that the line of windows right where it goes into doors and fender panels has a negative angle, this is characteristic of Mercedes. On Mercedes it creates an unpleasant tension, while yours is ok, because it creates a symmetry with side stampings and lower skirts. Probably it is hard to understand what I am talking about here, so I added your own sketch with editing. Don`t take me too serious, I know nothing of solid design, it`s just my opinion.