replacing fog lamp with 100w bulb?

No. There are a few issues. First, the wiring is designed for 55 watts, and 100 watts may overheat the wires and blow a fuse or possibly melt the switch or the relay. Second, 100 watt bulbs may melt plastic components, like the lens or other parts. Third, it may be illegal on the steet.

you will melt the housing and probably fry the electronics and it wouldnt even be too much brighter if everything does hold together. change out to new ellipsoid fogs and put in some osram silverstars, make sure its osram and not the sylvania that you can pick up at walmart or pepboys.

It works fine. I have done it in my car. You will need to clip the flare of the 100w bulbs in order for them to fit in the harness.

you can but that will be hard on the battery and alternator