1. A method for monitoring functional components of a motor vehicle, the functional units including an internal combustion engine, an exhaust system, a manifold, a catalytic converter, an exhaust particulate filter, a front muffler, a mid muffler, a rear muffler, an exhaust pipe or tailpipe, and an intake system the includes an intake muffler and/or intake pipes, the method comprising: placing at least one microphone next to one of the functional components to be monitored; placing at least one pulsation sensor on one of the functional components to be monitored; placing at least one strain gauge on one of the functional components to be monitored; placing a speed sensor on the engine; measuring the electrical signals at the outputs of the microphones, pulsation sensors, strain gauges, and speed sensor on the engine; analyzing the signals via Fourier analysis; and comparing the analyzed signals with an acoustic signature.