The back bumper stock is plastic.. its thin plastic.. it weights nothing.. you could throw it into a spider web and it wouldnt fall through. CF is essentially plastic with fibers through it.. it will probably end up being thicker than the stock one in the case of the back bumper which ill mention again is very thin and thus will end up heavier or at least close to being the same weight, with a performance view there would be no gain. If by some miricle its actually lighter than the paper thin stock one it would only be a gram or 2 which you would loose when you paint it. The bonnet and the front quarter panels would deffinately be ligher but i really doubt the front and back bumpers would be significantly ligher in CF. If its fiberglass with CF layer on the top then it definately wont be lighter than stock in the case of the bumpers.