Cost: Less than $1.00
Time: 10 minutes
Theory: This is a simple rewiring of the fog lights, allowing the fog light switch to be independant of the headlights.
Opinion: With the standard wiring, you have to have the headlights on to be able to turn on the foglights. Sometimes headlights (even low-beams) reflect extensively off the fog, so it is nice to be able to just turn on the fog lights.