I believe 2003 was the first year of production.
We are enjoying ownership of our 2004 Cayenne S, and are at 52,000 miles now. I have offroaded it through Gorman, Hollister, Azusa, and done overnight trips through Old Mojave Road.
It is impressive in its off road capability - with a nice 4WD system. It is a bit heavy for on road speed, but has nice handling dynamics for a mid size SUV.
The second row is tight, and the rear cargo space is downright terrible. The park distance control system is annoying - but aren't they all. Factory navigation is good, compared to other european and american systems I have experienced.
My wife was recently rear ended, and the Cayenne S received little damage, but the japanese import that hit her was in bad shape (hood smashed). The Cayenne is solid and feels like a tank. There have been little minor issues, but Porsche pre-emptively takes care of a lot of issues, issues that other manufacturers wouldn't even likely acknowledge or notice.
Maintenance is not cheap. I will miss the Cayenne S, but we may transition to a new BMW X5 4.8i, in early 2008, due to the BMW maintenance program. I personally feel the Cayenne S is a nice and well built vehicle.
Enjoy your 2008 Turbo. I know I would love it. The Cayenne S is my wife's primary driver.
Of course, it cleans up nicely, and it may get used for its original design purpose, but that doesn't mean that it is ever abused.
Great quality of paint.