System-level integration requires an overall understanding of the interplay of the sub-systems to enable componentbased development with portability, reconfigurability and extensibility, together with guaranteed reliability and performance levels. Integration by simple interfaces and plugand-play of sub-systems, which is the main objective of AUTOSAR, requires solving essential technical problems. We discuss to what degree the existing AUTOSAR standard can support the development of safety- and time-critical software and what is required to move toward the desirable goal of timing isolation when integrating multiple applications into the same execution platform.