What is wrong with plastic? The car in your avatar has a plastic body. Both it and the Corvette are reinforced plastic resin bodies, the difference is in the reinforcement material. In the real world, where repairs have to be made occasionally, the glass reinforced plastic is actually a BETTER material than the carbon reinforced plastic.
Zonda had never use plastic the using the same stuff what the SLR has made of
carbon fibre it strong and light so no extra weight has been added to slower the pagani down