Spring interchangeability?

[blur911]

I have a 2006 Cayenne S that has H&R sport springs installed, I've had enough of the rough ride and want to go back to stock rate springs.
I've located a set from a 2009 Cayenne S, will these fit?

I've contacted Porsche and apparently they have 10 different spring rates depending on options and of course want to sell me "the proper ones" for $900. I figure anything stock will be close enough. I just want to know if they fit?

Thanks.