The whole purpose of a correctly designed foglamp is to eliminate any stray light shining above the height of the mounted lamp in an effort to prevent the light from reflecting off the fog, hindering your vision.....you want ALL the light to shine as low as possible to prevent those reflections.
As an example of the above, turn your highbeams on while foggy out, and see how much worse your visibility is due to the fog reflecting the light.
If you are serious about really improving your vision by upgrading your cars lighting system, spend some time reading the following website, owned by one of the formost automotive lighting gurus in the world-
http://www.danielsternlighting.com, If you are only interested in your car looking cool, dont bother.