Well......you see.....for each circuit you need a different setup.
That´s why "Real races car setup developers" have a job during the whole season!! And in fact.....if there would be only one setup for each car then it would probably come as a default in the game.
You must specifty where do you want to race with your car. For example you need two different gear box setting for a "long-straights circuit" and for another full of small turns. The same applyes to the shocks, to the camber, etc etc etc etc
Antway......Google-LFS SETUPS- Download. Youll find webs with grids full of setups. Will cover you needs at the start.
Cheers