There is write up in Panorama I believe and had one of the Weissach engineers saying that the engines are making more than what Porsche is quoting. Porsche always gives conservative performance numbers. The GT3 engine is a detuned race motor with much higher tolerences. I'd say those CD numbers are very valid ones. Wait till the light weight GT3 RS road car comes out. Walter Rorhl stated that the the 2004 GT3 will be 5-10 seconds faster around the Nurburbring Id say the GT3 is one very fast car.