One of my wifes friends fathers...yeah its roundabout...owns a shop that works on mercedes and porsche/audi. i put the whole UD Pulley Q to him..he said that the amount of performance gain is really negliagable. people feel a gain becasue they want to [becasue they spent $150+ on the mod], in reality, on a 300+ hp car, a 5hp gain should not stand out. This in mind, he said that the "possable" side effects of less balanced engine, and the deleterious effects on the cars charging system more then cancel out the small added benifit of a UD Pulley. To sum up, hesaid he would never ever put on on a car..UNLESS in was made by the original manufacturer..aka..NISAMO came out with one etc. $.02
