1. A method for virtualizing system operation, the method comprising the steps: a) detecting data or operational instructions for a complex circuit; b) determining whether a new version of the complex circuit, an old version of the complex circuit, or a circuit simulator of the complex circuit is to receive the data or the operational instructions; c) when the circuit simulator is to receive the data or the operational instructions, virtually coupling at least one functional module to the circuit simulator, wherein the complex circuit and the at least one functional module embody at least a portion of a system; d) operating the system based on a pre-defined set of operational instructions; and e) evaluating performance of the at least one functional module in combination with the circuit simulator during the operating step to detect unsatisfactory performance.