Any reason I can't change out my City Lights (front parking lights for us US guys) for std fog lights?

I realize I have no fog switch, but I actually would rather have them on all the time when side lights are active,

 

I installed my own oem fog lights last year and it wasn't much of a problem. I chose to install a switch but you could easily wire them so they're on any time your low beams are on by using your low beams to trigger the fog light relay (or you could have them on anytime the parking lights are on). I bought mine used off eBay for about $100 for the pair. You'll have to buy the connectors to connect to the bulb sockets for the fog portion of the light separately as well as a light relay. The bulb socket and wiring for your city (parking) lights will plug right into the new oem fogs. Making your own wiring harness is not difficult. Power and a good ground are available at the under hood fuse box. Actually installing the lights can be tricky. Many of the folks here chose to remove the front bumper for the install. I installed mine by first removing the headlights and then installing the fogs from below. The left side is harder because the washer reservoir is in the way but it's doable. Good luck.