Glow in the dark fluro green. Have actually seen that, there was one in the lot when I bought my first r33. I am leaning towards some form of dark green.
I have had 2 cars without one and had no issues. In the depths of winter I have heard of people blocking some of the flow to the cooler but they were Sydney people.
Yes, yes they are. At super lap they make up the pointy end of the field every year. It all comes down to the fact that compared to a GTR they are light. Disagree. You can't get the camber required to be decent.