Carbon fiber has some great properties, the biggest dirtbike application being the obvious lightweight nature. If having the lightest bike around is a concern, this might be something to think about. There are problems with it though. Since it is a fibrous material, the grain direction is important. Carbon fiber can crack along these boundaries, and when it cracks, it can create splinters. It doesn't usually fail by tearing or creasing, mostly due to the nature of the binder, usually an epoxy or poly resin. Splintering carbon is a bad thing, as it gets very SHARP. Most of that involved cost you quoted is likely man hours involved in creating a part like that. Since a lot of DB aftermarket parts are handmade, or limited production, the cost is higher. Getting your own carbon fiber and laying up your own parts is possible, and not too hard with a prepreg mat, (SPENDY for the layperson), so most people that really need that lightness are willing to pay. Carbon also looks AWESOME. In one sense carbon and Ti are to dirtbikes what chrome is to harleys. Do you REALLY need carbon parts? Spend 200 on a membership at the gym, and I guarantee it will be more worth it... But if you have to have it...