I play a lot more of FM4 than GT5.
Curiously, when I drive the 'Ring in GT5, I never, ever get lost or surprised by the shapness of a turn, an elevation change, a curb steepness or whatever.
If Forza's version was that horribly innacurate and because I'm playing this version 80% of the time I guess I would be totally lost with The Real Nurburgring Simulator.
No. I can even occasionaly win multiplayer races on it.
What I find totally anti climax on GT5 'Ring is how much my ZR-1 sounds like a blender full of marbles. Now THAT is totally horrible and innacurate...