The objective of this work is the analysis and verification of distributed real-time systems. Such systems have to work in a timely manner in order to deliver the desired services. We consider a system architecture with multiple computation resources. The aim is to work out a compositional state-based analysis technique to determine exact response times and to validate end-to-end deadlines. Further, we consider such systems in a larger context, where a set of systems work in a collaborative and distributed fashion. A major aspect of such collaborative systems is the dynamic evolution. New systems can participate, existing systems may leave because of failures, or properties may change. We use contracts to encapsulate systems which work in a collaborative manner. These contracts define sound timing bounds on services offered to the environment. When some systems evolve, only those parts which changed need to be re-validated.