I'd keep chrome grilles on the car if its a six cylinder. I always look at the grilles on other E9x's when I'm out and about on the road, the reason being that the sixes have the chrome.
Black grilles are fine of course and it's down to the owner to choose but my personal preference is for the chrome.
I like the LED lights, how long did that job take to complete?
Current: F10 550i
Previous: E61 550i, E90 335i, E87 130i, E87 118d, Z4M, Z4 3.0i SMG, E46 330D, Z3M, Z3 3.0i, Z3 3.0i (US)