Not to knock this thread or the excellent install instructions it contains, but now there is a much better WK2 foglight upgrade option! Pricey but well worth the $$.
The 4" JW Speaker 6145 LED foglights.
They don't require removal of the front urethane bumper skin to install them. There are no ballasts to wire & mount, and absolutely no heat issues w/the plastic OEM fog housings. No bulbs with a finite lifetime to ever be replaced. These excellent JW Speaker LED fogs put out more lumens, use less power, (2.15amps @12volts), and produce much less heat. They'll work using the OEM foglight switch & wiring, and are a complete plug & play upgrade, mounting exactly like the OEM fogs using the three 7mm OEM fog mounting screws. They also come with a 4 year manufacturers warrantee!
Check out this install thread;
2011-2013 Foglight upgrade Option