I completed A class in a few days. If anyone is having trouble with the races, I suggest going back to GT4 and doing the license tests, the tests are REALLY easy if you carefully read the instructions, then come back to GT5p and have at it, i promise that you'll do better.
As for the amount of cars, I'm sure there will be plenty in the final version. The high-end graphics shouldn't be a problem for the system seeing as we haven't even pushed it very far in terms of graphic ability.
I've achieved rank 22 for the Clio Renault drift records on the eighernorgwand track.
oh and hi this is my first post here. don't worry, i've used the internets before, i'm not retarded.

