i work for a carbon fiber company. You can make non structural parts of the land rover defender out of carbon fiber or fiberglass. if its structural you can still make it out of carbon fiber but the amount of plies of carbon that would be needed to make it as strong as the original metal part would be vast and the weight would not be that different. you can make the front wings, back door, bonnet, front (where the lights are) and side skirts out of carbon for definite. Metal has some give in it. where as carbon fiber doesnt really. So where you landy articulates things like the doors bend a little. If your after weight saving you can have the parts above made out of black carbon glass. which is the same strength as the carbon fiber you see with the pattern, but instead its just black. it you want it for looks. you will have to have it make out of the proper carbon (e722 carbon 200g). however the price to have it made out of the proper carbon will be roughly double the price compared to having it made out of the carbon glass. But carbon glass comes out black (no pattern). speak to an autpmotive structural engineer about the structure of a defender and you will be able to see if you can make all your desired parts out of carbon fiber. if its structural you will have a big problem and a big cost to pay.