Hey Mot.
this thread started with the photo on top that shows the stock fog lights when driving through mud. This stock fog lights have no!! colored glass but use only !! yellow bulb as you can see in my setup (see photo). These are the stock fog lights. When you switch them on the whole lights shines yellow as the photo on top.
Of course here in asia you can find any color cover for fogs or lights you want. I have seen yellow, blue and red covers on cars.
But nothing like this is stock !!
Here in asia unlike the US-models we have white cover for the indicators with orange bulbs (stock) that people change to blue.
No regulations and if you want to have some nice blue headlights inside then just put them in. Another crazy option is blue light under the car. In the night it looks really cool.
Here we are the lucky ones and can almost do anything we want to our rigs. If you like it !!!!!
Have fun.
Mike