The specific weight of composites varies between 1.5 and 2.0 compared to 2.7 to 7.8 for aluminium and steel.
Double curved shapes are easily produced in composite materials at almost no extra cost. For production of limited series the relatively low moulding costs are an additional benefit.
Thermal expansion of composite materials can be tuned. Depending on the fiber used it can vary between 0 and 30 where steel has an alpha of 12.