@RS88 If you're familiar with Photoshop or an equivalent, it's always worth trying a colour-change out first using a photo' of your car. I was going to go for the replacement black kidney grille, but when I Photoshop'd it, I had second thoughts - somehow it didn't seem any better or worse, just different, and I decided it was a lot of effort/cost to go to for a possibly neutral result.
[Edit: Here you go ...
not a great piece of Photoshop editing but you get the idea e.g. strikes me that if the diffuser panel is body colour, then it makes my gloss black tail pipes look a bit unmatched. Possibly why BMW kept the diffuser panel grey (as well as cost)]