I'm not sure if the yellows are better or not for fogs. My reason for ordering them is that they MIGHT be better and I think it would look cooler. The reason that I think yellow may be better for fogs is because the bluish/white light from HID's and lookalike bulbs gives a very clear, sharp light on the road, but doesn't provide contrast and shadowing very well. My experience with this comes from mountain biking at night, where using an HID helmet lamp lights up the trail very well, but makes it difficult to distinguish between the type of dirt you are riding on (sand, hardpack, etc...). Using a standard halogen lamp, however, provides a less intense yellowish/white light that provides better contrast on the trails. The same seems to be true with snowboard goggle lenses at night. A yellow lens provides optimal contrast. So, based on these two things and the fact that the IS300 has yellow fogs, I decided to go w/ them. The bulbs I ordered are only rated at 55W, w/ a 130W equivalent output, but you can get the superwhite bulbs in an H3 for the fogs rated at 100W actual, and like 160W equivalent output. If I recall correctly, the fogs on the P5 are rated up to 100W actual, so the 100W superwhite H3's would be brighter, but I'd rather have the yellows, since I don't use them to project, but just light up the area in front and to the sides of my car very well.