If I still had my 07, I would have the grey parts of the grille painted, clear coat and everything, silver. I loved that the grille was silver colored against a black car but I didn't like the unfinished plastic.
I've seen people paint the grey part black only usually it's on a black car.
I like how Dubai kept the vertical silver slits unpainted. Worst case, he doesn't like it and he goes back and blacks that out too.
By the way, if you look at the new 2015 ats coupe and sedan front end, you'll see that the shape of the grille is going back to 2005-7 Sts style grille. Interesting.