is it possible to use the 9006 bulb as well? I have some spare 9006 bulbs at home and I would like to add the fog lights to my LS and use the 9006 bulbs that I already have.

Regardless if you're trying a 9005 or 9006 bulb,you're defeating the purpose of a FOG lamp.They're designed to illuminate UNDER the fog,not through it.Which is partly why high beams are about useless in foggy weather,and standard low beams don't do much either.To those of you that have made this change,has it improved visiblity in foggy weather?