There is nothing that talks about it that I could find....

18" Are they 18x8?
19" ???
20" ???
21" ???

I know the setups are either 265 or 275. Not sure about the 21" though

The 21x10 runs a 295/35 tire.
The 20x9 runs a 275/45 tire.

I'm going to assume the 19 is 19x9 as it runs the same 275/45 tire as the 20 inch wheel.
The 18 runs a 255/55 tire. I don't belive any run a 265 tire.

Actually, i think and someone can correct me, for the 19" they run 275 for the summer tires and 265 for the general all-season ones. I know it is 265 for the 19's all-seasons cause I was looking at a white one at a dealer the other day.

So the 19 is also available with a 265, so it's possible that the 19 inch wheel is a 19x8.5 to accommodate both the 265 and 275 tire.

Ya, but does anyone know where I can get the exact specs. They really don't tell you on their site which is odd.

If you do a 3D build and click on the wheels in the summary, it shows the sizes.

8Jx18 ET 53 with tires 255/55 R18 Cayenne and Cayenne S III
8.5Jx19 ET 59 with tires 265/50 R19 Turbos and Design II
9Jx20 ET 57 with tires 275/45 R20 Spyder and SportDesign II
10Jx21 ET 50 with tires 295/35 R21 All the 21"ers

Thanks so much. This is what I was looking for, but couldn't find...