I have some comments to make on this topic. Tire (or tyre) choice is so often subjective and not born out by timed performance testing. For example although driver A might not be able to beat driver B, driver A might still put his best lap time in on tyres which driver B found to be inferior. Hope that made sense. Put another way, if you put your car backwards into a hedge because you couldn't feel the Michelins on your car losing grip, it doesn't matter to you whether they are superior or not to a Dunlop on which you could feel the grip reducing.
I find the F1 to be a great tire but I've also driven cars with it where I didn't like it - a Lotus Exige comes to mind. T_T might think Michelin's PS2 is superior, but others might not. Personally I've only found the PS2 to suit heavier cars. That doesn't mean you will, however - you have to drive them back-to-back and see what suits the combination of you and your car. There is no other way.
Goodyear F1s are NOT factory fitted by anyone - yet the PS2 is factory fitted by a shed load of manufactures, including Porsche, BMW, Audi, AMG-Mercedes, Renault, Ford, Bugatti . . . .
When the likes of Porsche deem that F1s are good enough, then they WILL offer them as factory fitment - but they don't - wonder why - simply because they are NOT as good as the PS2. 
I have qualms with both these statements. Goodyear happen to have worked closely with many manufacturers including some US car manufacturers on high performance cars, notably Chevrolet and the Corvette.
Porsche are less likely to go to the trouble of dealing with a manufacturer based outside of Europe - for cost/communication/development/logistic reasons (Bridgestone being an obvious exception - but there is commercial history between the two companies). The Porsche approved tyres are also different to standard versions - as I'm sure everyone is aware - and so just saying 'Porsche use them so they must be good' is a moot point.
BMW, AMG-Merc, and Audi, and the rest may do 'deals' - but Porsche categorially do not.
I assure you - they do.
But Porsche arn't interested at all in 'dumbing down' their cars with inferior components to save a few Euros here and there. 
Except the Cayenne of course, which is a VW touareg in drag. And many other Porsches have often contained many parts in common with lowly Volkswagen group cars.
Goodyear own Dunlop, and Goodyear also claim to be a 'higher' brand than Dunlop - and being as Dunlop are already on the 'factory approved' lists, why arn't Goodyear?
Goodyear are on the factory approved lists of many of the worlds largest car manufacturers. Dunlop was a small, failing British company and is now effectively just a brand name used by top-three manufacturer Goodyear - which incidentally means they are on the 'factory approved' lists you mention above.
Afterall, Goodyear invariably are ALWAYS cheaper than Michelin and Continental
Selling price is not necessarily an indication of quality or suitability for purpose.
Like I have always said, and has also been confirmed by the likes of Evo, the Goodyear F1 Asymmetric has some serious flaws - which verge on the dangerous.
You don't want to listen to "some of the blatant bollox which spews out of journos quills", surely? I doubt an American company who have been on the wrong side of litigation before would want to put a tyre on the market which had serious/dangerous flaws. For my own reference, what are these supposed flaws?
and if that other German tyre company Fulda could make a tyre to work on a Porsche
Fulda are Goodyear's 'affordable tyre' brand in Europe, so they're playing to a different market segment.
With your opinions on supposedly inferior Mobil and Goodyear products, am I detecting an anti-American vibe here?
