So there is another extra shader applied to mirrors in houses and in cars? Theoretically it's supposed to be possible to do that with clothes too with the help of mods (script to be exact).

It's hard to search for it because the search results are flooded with questions about specular maps and car mirrors (searching for "GTA 5 mirror texture" or "mirror like texture" and so on) but not about mirror textures.

Images are illustrative

I'm trying to achieve something like this, with a very reflective, mirror like look:

I found the shoes with OpenIV, I exported the .ytd file, opened it with TextureToolkit, exported the ..._spec.dds and modified it, and then I imported it back to the .ytd file with TextureToolkit and back to OpenIV. I also exprted the .ydd and changed the shoe's color to black. The best results I have achieved looks like this (very reflective, but only reflects bright colors):

Question: How should I change the _spec.dds texture file in .ytd and the shoe's texture .ydd, to achieve such mirror like reflections or what else should I change, the opacity of the textures?