There is one issue here which I am surprised no one has raised - the poor quality of Porsche 6 pot engines. Right the way through the era of the 996 and 997 model 911s and the corresponding Boxter / Caymans, they have suffered badly from scored bores and intermediate shaft failures. Have a look at
http://www.pistonheads.com/gassing/topic.asp?h=0&f=48&t=1052310and bear in mind that to some degree, owners will fight shy of admitting an issue which would devalue their cars.
Has yopur Trad given you that sort of problem? No it hasnt but you maybe have had an occasional bolt fall off