There are no guarantees in life when buying a used car. The PPI is an invaluable tool to assist but it is only a tool. You need an expert eye and hand to do a Porsche PPI correctly.
That said, it is usually FAR superior to what any nornal car buyer can do on their own. A quality PPI, a long road test, service records, a car fax, these are all necessary if you want to properly understand what you are buying.
Specific to paint, the tool you need is a paint meter. Without it, your "eye" is simply not sufficient to pick up a repainted surface. There are too many good paint guys out there. It is that simple.
Having said all that, I know that many car buyers think they are so smart they don't need a PPI. I know because I have sold Porsches to many of them. I used to offer them a credit for a PPI at the local dealer.
4 out of 5 declined.
Go figure.
