Yeah, I am pretty happy with my knowledge of all the other tracks, with maybe the exception of Grand Canyon. For Nurburgring, I know the first 1/3 or 1/2, but after that I just don't have it memorised properly. I have a general idea, but I don't know it well enough to drive with confidence and get good lap times, and once you are on the grass in a powerful car it usually takes quite a while to get back on the tarmac.
There are a couple of Nurburgring events in the Extreme Hall that I really need to clear, and the CPU is fast on them both...