I really struggled when deciding on Weissach pkg when I speed my RS (seemed very expensive at the time), and now I can't imagine my car without it. Carbon fiber is expensive, but the visual statement it makes is important on a car like the GTD (that is based upon a car at a much lower price point). The exposed carbon makes it look more like a 400k+ car.
I am not crazy about what it costs, but I feel it is a car that benefits from the exposed carbon look (because of how wide the side skirts and how deep both diffusers are, and the massive and wide nature of the hood, carbon covers a lot of surface area).