Will it keep my ratings if I do a fresh install ?

[OZ67]

Which folder should I save for controller and profile ratings ? Cheers

 

[Majuh]

Your controller settings are stored in "Documents\Assetto Corsa Competizione". Your profile ratings are connected to your Steam profile and stored on their servers.

 

[LynxSec]

Profile rating is saved online, every time you start the game they are fetched from Steam.
As Majuh said, if you want to be sure, backup the entire "Documents\Assetto Corsa Competizione" and reinstall the game.