I'd turn the traction control up to 5 or higher if you're just trying to win. It really helped me with the Cote'd Azur race, I'd assume it'd help out on the other tracks as well. And with the FGT you can afford to turn on a couple aids, especially on Cote'd where the speed is kept down and you can tune the transmission to a lower top speed.
Theres some setups in here:https://www.gtplanet.net/forum/showthread.php?t=142091&page=4