Originally Posted by fastball
What manufacturers must do, in my opinion, is go by the DIN (Deutsche Industrierten Normen, or German Industry Standard). The German DIN is, basically, your net hp. "At the wheels" as people like to say. It's the true numerical output of hp and Tq after everything has been taken into consideration (accessory motors, engine and vehicle weight, drivetrain loss, aerodynamic forces). The numbers might be low, but at least they are accurate and consistant.
I believe that the current European Union standard is to measure engine output in kilowatts, based on 0.735 kilowatts per PS (Pferdestaerke). That's why you get the K20Z3 engine rated at 200 PS has a rating of 147 kilowatts (kW). However, because the kilowatt rating totally confuses consumers even in countries used to the metric system, the PS rating continues to be used.