but does not slip

the german cars have clutch pedals that are upside down you it might feel a lot different then what people are used too

The clutch peddle is the same as an american car, the first poster is mistaken. They change from the bottom hinge point to a top hinge point with the 996. The turbo has a powered clutch actuator. The power steering pump provides hydraulic power to the actuator & amplifies the peddle input. There is also an accumulator that stores fluid under pressure to be used by the clutch activation system. The accumulator has a nitrogen charge on one side & the hydraulic fluid from the pump under pressure on the other side. A common problem with the 996tt is is to have the accumulator go flat on the nitrogen side & the accumulator will not be effective. This is the most common problem with the clutch on a 996tt. l would have a independent Porsche Mechanic that is knowledgeable on the 996tt take a look at it.