The BMW 6 Series is a full size grand tourer produced by BMW since 1976. The first generation was available solely as a two-door coupe until it was revived in 2004 for the second generation where the coupe was joined by a convertible. The third generation added a four-door coupe known as the Gran Coupe. An M6 high performance model has been produced for the first three generations of the 6 Series. BMW 6 Series takes on rivals like the Audi A5, Mercedes E-Class and Mercedes S-Class, as well as certain models of the Porsche 911. The 6 Series managed to achieve a above-average high score of 95% for reliability. Generally, BMW has a good reputation for building solid vehicles and this remains the case for the 6 Series.