AUM:
GTR vs Porsche is also Japan vs Germany. Nobody in Europe would take any GTR vs Porsche comparison by a Japanese magazine seriously. They clearly have a national bias.
Yet we are all waiting with baited breath for a German magazine (Sport Auto) with a German driver to be the ultimate arbitrator in the GTR vs Porsche battle. All other tests by all other magazines are deemed irrelevant by some SA fans. Does this seem reasonable given the underlying national interests and bias?
Sure! There is no other magazine (on an international level) with such a professional and comprehensive test procedure like SportAuto. Also, there are very many examples of non-German cars being very quick (compared to German test cars) in the Supertest. In addition, there are surprisingly poor result for German sports cars (997TT) in the Supertest.
Simple conclusion: People who suggest that the Supertest results are biased by "national bias" don't have a clue about what they talk... They should buy some SportAuto issues, do some reading exercise and then realize what I just typed above.
BTW, there are plenty of other tests that are in line with the SportAuto Supertest result of the GTR (if you exclude these Japanese video clips which could hardly be called "tests" and the US magazine tests on partly sand covered desert tracks ). The picture is very consistent. You just need to use own experience and judgement (if existent) to interpret some of the numbers floating in the net.
The SportAuto Supertest will just highlight what is already obvious from the numbers available to date: slightly faster than 997TT (pre-FL), of course slower than Scuderia or GT2. We know now that there will be a gap between the GTR's one-lap performance and the car's potential over a significant number of laps. This will not be reflected in the SportAuto numbers, though.