The Synthetic Aperture Interferometric Radiometer (SAIR) Performance Simulator (SAIRPS) is a very versatile software tool developed by Deimos Engenharia (Portugal) and the Universitat Politècnica de Catalunya-Barcelona Tech (Spain) for the European Space Agency to simulate and compute the figures of merit of the performance of arbitrary SAIRs, using the OpenSF framework. The description and developments of this simulator were previously reported in the open literature and previous IGARSS. This paper summarizes the developments in this third year of the project, including the end-to-end validation tests, and the radiative transfer module that has been added to improve the versatility of the tool.