The problem is that when exporting from bats (only in gmax? I'm not sure) textures get over saturated and colors blown out. See the histogram here
So I just lowered the highlights. The blacks color in this picture in this picture are dead pixels, because it's blacker than black. I fixed that in the first image I posted but didn't bother to here.
With a few tweeks the highlight clipping is gone
Saturation fix for the blue/cyan color only
So, it's more to it than just just making the textures darker. Most of this stuff (though not done the same) should be possible in GIMP. Maybe someone can point out to tutorials, I think there were some by gascooker at least back in the day?