And the more accurate the Track is depicted in the sim , the better You get the idea what is coming next. It won't work with the Version of fm4 as it is very inaccurate but the one in gt5 is actually ok. That is all i ask for and the nordschleife is harder to memorize than most tracks.
But whatever i bet the dlc nordschleife will be quite good. If you don't like a realistic Nürburgring, don't buy it.
Here is the Blog of some guy who wants to start at the 24h race.
http://mywayto24h.tumblr.com/
Well the first thing he started with was to memorize the ideal line on GT5.