The automotive is a sector where energy consumption during the use phase prevails over the production and the end-of-life phase. Therefore, a lot of research and innovations have aimed at replacing classical steel parts by lighter materials like light alloys and polymer composites. While composites are very attractive for the use phase of cars, their introduction suffers from the limited end-of-life options for composite structures. Due to the restrictions imposed by the European ELV directive, the use of non-recyclable composite components in car manufacturing is not obvious. An extensive life cycle analysis for a reference car design was conducted to study the effects of replacement of conventional steel structures by lightweight carbon fibre composite alternatives. The study also takes second order effects in the design of the car into account, such as the required motor power. The obtained results show the trend towards more intensive use of carbonfibre composites in car design desires some nuancing, and the opportunities and threats are identified.