Not recommended to put upgraded lights on the stock wiring (the basic bulbs burn out all the time as it is, due to the crap setup)... BnB has a simple diagram to help you do the inexpensive upgrading in a matter of about 1hr: Fog Lamp Wiring Upgrade
As long as the upgraded power wires (positive thru relay & ground to bulb) are thick enough, at least 12ga, you'll be able to run 55 or 100... 130 may be OK as well, but I'll probably swap my 12ga out for 8-10 and try going up from my 100's for kicks if one burns out.
- Dave
