GPL is the ultimate thrill ride - NOTHING I have ever played or driven has some close. Unfortunately, it does not work for me right now. I am reluctant to give much benefit to most games you can find in a store, except for learning tracks. GPL is an exception though.
Now granted, I can't really feel the forces, but I was disappointed with GTL. I find even with all aids off, that it doesn't penalize overworkign the tires near enough. I'd expect racing tires to be even worse about it than road tires. In GTL, I can kick full lock of steering, and still make a turn with little loss...that irks me.
Another I play, is Racer, but it is not near finished, lots of unfinished aspects, I like it as I can see the raw data of everything live, allowing me to increase the realism adjusting things until I start seeing the real world numbers. I also like it as I can easily import content into it.
I recorded some new audio clips with my '84 944, and have them in the game for a car I'm working on.
http://www.andrewscars.com/racer/recording.wmv
GTR/GTR2, I liked GTR's demo, perhaps its better at realism than GTL, I have yet to ply GTR2. I also have not played GTx or Forza x with a racing wheel, so cannot comment on those.