I always nod and smile or wave at other Porsches. Often they don't react (especially 924 drivers).
Would I nod/wave at a Cayenne? Not unless he/she waves at me first.
On a side note: Don't you think the Touareg is nicer to look at? It's like the Cayenne is one big air intake. Oh and the Volvo XC90 is actually pretty nice. Except when viewed directly from the front.
