System-level synthesis is the task of automatically implementing application models as hardware/software systems. It encompasses four basic sub tasks, namely decision making and refinement for both computation and communication. In the past, several system-level synthesis approaches have been proposed. However, it was shown that each of these approaches has drawbacks in at least one of the four sub tasks. In this paper, we present our efforts towards a comprehensive system-level synthesis by combining two academic system-level solutions into a seamless approach that automatically generates pin-accurate implementation-level models starting from a formal application model and generic MPSoC architecture templates. We analyze the system-level synthesis flow and define intermediate representations in terms of transaction level models that serve as link between existing tools. Furthermore, we present the automated transformation between models for combining two design flows. We demonstrate the combined flow on an industrial-strength example and show the benefits of fully automatic exploration and synthesis for rapid and early system-level design.