Customization of IP blocks in a multi-processor system-on-chip (MPSoC) is the historical approach to the cost-effective implementation of such systems. A recent trend consists of structuring a MPSoC into loosely coupled voltage and frequency islands to meet tight power budgets. In this context, synchronization between islands of synchronicity becomes a major design issue. Dual-clock FIFOs compare favorably with respect to synchronizer-based designs and pausible clocking interfaces from a performance viewpoint, but incur a significant area, power and latency overhead. This paper proposes a library of dual-clock FIFOs for cost-effective MPSoC design, where each architecture variant in the library has been designed to match well-defined operating conditions at the minimum implementation cost. Each FIFO synchronizer is suitable for plug-and-play insertion into the NoC architecture and selection depends on the performance requirements of the synchronization interface at hand. Above all, components of our synchronization library have not been conceived in isolation, but have been tightly co-designed with the switching fabric of the on-chip interconnection network, thus making a conscious use of power-hungry buffering resources and leading to affordable implementations in the resource constrained MPSoC domain.