I wouldn't travel around the world to see it, but for someone who lives in the northeast, it is worth every penny to attend a track day. For Gran Turismo, I think opening up turns 1 and 2 would be the best configuration. They often use the infield chicanes to keep amateurs from gaining too much speed before the turn 3 brake zone.
And the NASCAR enthusiasts would love another oval track in the game. Two birds with one stone!