This is actually something silly and easy to handle. In SA's default PC graphics, we notice a sort of two-tone moving gradient (or whatever it is called) on the vehicles (especially cars). This is due to a texture called "xvehicleenv128" inside a file called "vehicle.txd", and is meant to make the body of the vehicle blend into world's atmosphere "more properly".
Now, there is no accounting for tastes, but I personally find this sort of uncomfortable. Decades ago, I tried to do something about it without success, then just few days ago I came up with the solution, and it just could not be simpler:
I replaced the texture with a black square!
This was the only way to proccure that the vehicles responded pretty well to the world's atmosphere, with no pre-colored bias. And now they look more blent into this one, since you will not even see that "gradient" in dark places!
There is something more: An intermittent rendering glitch that makes this default texture not display correctly, thus you notice how vehicles look clearer at the bottom but darker at the top. This mod should do as a workaround for that as well!
Installation:
You also count on the standalone texture extracted, for any other project by modders.
Again, this was pretty easy, but I saved the trouble for many people.
A.P. VISION.