I would also be worried about Porsche parts prices having heard a few horror stories. I don't know how much truth there is in them. Having said that, Audi parts aren't exactly a bargain either. You're going to have to stump up a grand and a half for a Porkcom, too.
I just wish they were more attractive. It looks like they made no effort to design a good looking 4 door car. The exact opposite is the Aston Martin Rapide which pulls off the 4 door conversion perfectly. IMO. They're a bargain at the moment, too, but they are RWD. I thought you'd be all over RWD - they are a lot of fun to drive.
The new Panamehs are very good looking indeed. Pricey, though.