Project C2 harvests foundational advances on quantitative behavioural properties related to component suitability, putting in focus how formal and empirical approaches can be integrated towards a comprehensive and reliable understanding of quantitative system properties. We will concentrate on performance properties (like latency, execution time, energy consumption) and compositional reasoning at the level of features, i.e., where the characteristics of features are encapsulated in components. For this, Project C2 provides explications to identify limitations and to come to new conclusions regarding the influence of noise, uncertainty, configurability, and non-determinism, addressing feature interactions in formal and empirical models.