[gone-ot]

...in the grill is less problematic; it's already an eddy location.

...with "fog" (yellow) lamps, you want them as close to the ground as possible, but up enough to keep them out of harms' way.

...with "driving" (white) lamps, you actually want them as high off the ground as possible, so as to illuminate further down the road, assuming they're powerful enough to reach that far (look at where they're located on endurance Rally race cars).

...otherwise, they're basically just "illuminated" bling.