This thesis represents one of the many achievements of a large and multi-year "meta-project" undertaken at the DISCo Computer Science Department (University of Milano-Bicocca, Milan, ITALY). Core of this "meta-project" is the realisation of an architecture (with a complete implementation framework) to build real-time systems by deploying a new approach, heavily based on reflection (see Section 2.4) concepts. The architecture we devised, codenamed Real-Time Performers (RTP), has already been used in many real- world applications (see Chapter 3) and has demonstrated to keep up with its promises. The main aspect that was still missing from RTP was the capability to manage internal Quality of Service (QoS - see Section 2.1) parameters, such as power consumption, memory allocation, etc. The two goals of this thesis are: Main: enrich RTP, both from the architectural and implementative point of view, to supply QoS functionalities; Collateral: support the capability to keep RTP systems (both standard and QoS-aware) coherent with their internal structure and functionality.