I really like the bare aluminum color with that car - like someone said before it looks like a star wars fighter or something - scrappy but sleek. If you lived in a state that required 2 license plates, then I'd say you had enough grille blocked. I think you could block a bit more and leave less than a license plate-sized gap (I would isolate all the gapping to one area, not two little gaps). You could even make this piece somehow adjustable or easily swappable so you can block the whole thing off for winter. You'd be surprised at how little that radiator needs to breathe. You may also consider fully blocking the upper grille with -ahemm-
plexiglass?
Nice work. BTW, do you happen to be a fan of McCartney's later solo work, or am I reading your avatar wrong?