[mikefocke]

plus Bentley and Pelican books.

Plus a course in engine internals (taught by flat6).

Now the very best diagnostic machine would be a PST2 which sometimes come on the market used but are expensive. Next the Durametric (plus laptop) in one of the 2 versions with increasing capabilities and prices.

And then there are thousands of dollars of special Porsche diagnostic or mechanical tools that are referred to for use in testing by the factory manuals.

For the basics, an Actron Code Reader for maybe $100 and a list of the Porsche-used codes and their descriptions associated with the model year cars you have.