We propose new accurate predictive models for the delay, power, and area of buffered interconnects to enable a more effective system-level design exploration with existing and future nanometer technology processes. We show that our models are significantly more accurate than previous models - essentially matching sign-off analyses. We integrate our models in the COSI-OCC communication synthesis infrastructure and show how they impact the feasibility and optimality of the network-on-chip architectures that are synthesized by this tool.