I have been trying to find a thread on the forum about fake GSD3's that i read a while ago, anyone remember this?
Did you check out your tyre codes vs the info in the thread Mr Orange linked to?
As someone with GSD3 who posted in that thread, I am not entirely convinced by the concerns listed.
My Chinese tyres all have the correct codes to suggest they conform to the same spec as the German versions (i.e. European standards and homologation). As I think I said before, I would be very suprised if a major company like Goodyear (as both a first tier supplier to OEMS and also a company selling direct to the public) were able to market two versions of the same product with differing characteristics but named the same! That would definately be one for Trading Standards and other appropriate bodies.
The main reasons I changed from P7000s were threefold.
1) I needed to change 3 of my 4 tyres so used the opportunity to change model completely. I don't like mixing tyres front/back and only replace in pairs.
2) F1s got fairly consistent good feedback & reviews in both forums and tests I read.
3) I wanted somethin quieter than the P7000s.
I've now been on my F1s for a few thousand miles and, while I think that the P7000s were probably slightly stickier, I have noticed a huge difference in road noise and I am getting marginally better fuel consumption figures (an unexpected bonus). As for the grip, I've seen nothing to be concerned about so far and I am generally quite happy with them.