Why Porsche engines fail

IMS Bearing - The Full Story | Oregon Region Porsche Club of America
Camshaft bearing failures in model years 1999-2008 are a problem to be wary about, according to this article. Note that he points out that a gently-used car may be more prone to this failure: " Although there is limited data, the general trend is that lower mileage vehicles with infrequent oil changes or driven light-footed (as in run at low speed/engine rpms) are most likely to suffer a failure rather than those cars that are driven hard and well-maintained." 

http://www.oregonpca.org/resources/ims-bearing-the-full-story/