Thanks for the responses. Sounds like the major opinion is that I should get a PPI in any case. I might have a problem finding someone I trust to do a PPI though. I only know one person that owns a Porsche, (a new Cayman), and he's a fairly new owner so I don't think he would be much help in checking out a used one. This isn't a large city where there are various independent Porsche experts around and my friend with a Cayman doesn't know of any.
There are businesses that specialize in PPIs in the area, but I suspect you might get one that does nothing more than make sure all the features like heater and airconditioner function properly.
I was hoping for more positive response about buying from a good dealer. Maybe I should just buy a new Miata.
Norm