There was a point where the aerodynamics went downhill (turned uphill?). They raised the cowl height, and consequently the frontal area, at least 10-20%. Compare the earlier rendering for the height of the headlight above the fendertop and note the semi-enclosed rear wheel.
You could totally duct tape coroplast onto those front fenders.
How about wedge-shaped pontoons that are flat on the inside in front and flat on the outside in back? That would pull air away from the body as it is widening, with some indeterminate effect abaft that.
And why aren't those ribs areas either side of the rear tire not all taillight? Like a big ribbed Mercedes one from the 90s?