I'm not familiar with them, but from the published stats, they seem like they'll be too bright for fogs. These stats saw they put out 3,030 "raw" lumens. I'm not sure what a "raw" lumen is, but it's probably the output of the bulbs before the light is diffused.
Even if the output is cut in half by the diffuser, that would be 1,500 lumens. A good headlight puts out around 1,000 lumens or less, so they'd be brighter than your headlights and therefore not good as fogs.