Though not a direct answer to your thread, have you tried opening up the headlight assembly and cleaning it first? Try to determine if the fogging is on the inside or outside. Sometimes the gasket that seals the lens to the assembly begins to erode, causing a leak that allows condensation within the lens. I took mine apart, and used just a standard private-label glass cleaner and let the chemical sit in the lens for about 20 minutes, dried it out and carefully put it back together and haven't had a problem since.
If it still leaks, you can buy the gasket separately.
If the lens is sand-blasted from the outside, Canadian Tire sells kits to fix that as well. If you want to avoid the hassle, I'd suggest checking out Bimmerspecialist and ordering the OEM part from there to save on potential custom duties (although Khoalty is pretty good as long as you use USPS).
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