I installed PIAA H11 2500K Yellow 55 watt lamps in my bumper located lights.I'd say yellow bulbs could produce better performance in fog, but LEDs generally will not.
Do you have the Halogen headlamps? If so, you may get better results in swapping those out for LEDs. A buddy of mine just did that and they look pretty good and really bright.
I like the yellow colour as it does not reflect back when snowing to the degree that white does.
The lights fill the dark area right in front of the 3 and also somewhat the ditch which is what I am usually trying to avoid.
The yellow colour is also very distinctive if one is looking for recognition lighting - here it is just not the norm.