HIDs do not actually burn hotter than halogen, and the Kelvin rating, i.e. 8000K, 3000K etc has nothing to do with the actual temperature of the lamp itself, instead it just refers to the color spectrum. So in principle, you will be fine, the only thing I don't like about stock housings is they scatter light too much for HIDs and don't provide a nice cut off, but if it's just the fog light housing, then it's not a big deal.