Mycroft
Life happens
What exactly is the big deal with CF accents? From what I understand, CF is great from an engineering perspective. Light, strong, but expensive. From a style perspective, if you like it, great, but I don't understand why the sport model would require it as the interior option.
CF is closely associated with accents in high performance cars. There's an industry of 3rd parties making replacement CF parts for a wide range of HP or near-HP cars.
As I said, I think Elon really wants the performance version of the Model S to stand out from "normal" 4-door sedans. After all, your Nissan Max, Audi A7, and non-AMG CLS can't do 4.4 secs. While the AMG and BMW M can do it, they require < 20MPG, a lot of noise, and > 500hp to do it. With the accents (and possibly badging), and some savvy marketing will start associating the Tesla brand along side Mercedes and BMW for performance and not just for "luxury".
Mercedes CLS63 AMG - 518hp, 4.4, base price $94,900
2010 BMW M5 - 500hp 4.7sec, base price $85,700 (2012 will likely be faster and much more expensive)
Model S Performance - 435hp, 4.4, base price $84,900
Now, it could be argued that this could be accomplished with other accents than CF. True, but this is what they've come up with. I just think they want the Sport to be easily identifiable for whatever reason.