You didn't say what you base your prejudice against the CR survey results upon. Just because the results don't present a simple, convenient picture of the world, doesn't mean the data are invalid.

The report is presented as a summary of responses CR received from Porsche Boxster owners, not their own tests. The rating is based on relative numbers of complaints from year to year and from manufacturer to manufacturer with a weighting based on number of miles driven. The results do NOT say that a particular make/model/year is reliable/unreliable, but only compare the rate of problems, which in absolute number may be small relative to the total produced. Unfortunately in the particular issue there's obviously not room to indicate how many responses they received for each and every make/model/year/problem, but those statistics might be available upon request.

Manufacturing is an art, as well as science. Parts are not necessarily made by the same supplier, on the same machine, and the raw materials do not even necessarily come from the same place. There is also likely to be turnover among the engineers, machinists and assemblers. Porsche like any auto manufacturer intends to make a profit and so is always looking for ways to save expenses - hopefully without taking a step backward. That's what quality contol is for. However, if they're not taking risks, they're guaranteed not to improve. Usually the changes are for the better, but there is no certainty. If quality only went in one direction, given how long humans have been building engines and gearboxes there would be absolutely no reason for one to fail. Bottom line, there is no guarantee that year Y + 1 is the same or a better beast than year Y.

Just as there is no substitute for a Porsche, there is also no substitute for doing due diligence on the purchase of a used (or new) Porsche. If the buyer is not mechnically inclined, is not buying a certified car from a dealership, doesn't know a good mechanic, but is going to buy anyway, the CR survey results can't hurt them - statistically speaking that is. Of course, the same might not be true for someone trying to sell one.