my fog light housings have been fine with the HID's in there. The upgraded harness isnt neccesary, but some guys have had problems without it.
I got my headlights from your first link "HID kit". im not sure where the fog lights are from.
Never heard of the 2nd link, but if it gives you peice of mind, get the more expensive kit, i have had good luck with them.
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Corey Smith