I cannot change the vision color or its brightness without breaking client compatibility. I'm keeping it client sided so you can apply and join any server. I played a few games and the aliens seem to be fine actually. I prefer this way over the default white and kenny's green color. They just stick out too much. I prefer different color values over the body instead of everything being one color.... I'm working on a trailer video for it to display the pros and cons of it.
Heat vision looks fantastic, but I'm not too sure about the alien one. Maybe you need to highlight some more sections on the alien skins, because right now they tend to blend into the scenery. Alternatively you could just change the ambient colour to highlight them a little more.