I have the BMW M3, what a good car, Manny you would love it, not as much horse power as the Aston Martin, but it handles so sweet in the corners.
I had the same problems with the world tour, but after the last patch, Shift now works the way it should have from the start and I have no more problems with the game at all.
I did do my time trial with the BMW M3, but I'll put it down as practice and go with the new car, its cool. It was a great time too, it would have been first place, LOL, probably because it looks like I was the only one with that car.