Got it, similar to what somebody posted before >
in game setting, change key bindings / button config to what you want, (you must do this first*)
now go to documents > criterion games >need for speed most wanted >save > 2260373530 (this is a folder name)
inside the numbered folder there is now 2 files, mine says - controls.nfs13save and MUD.29.nfs13save (*note if you don't change your controls in game then there will only be the MUD file there)
now open the controls.nfs file with a file editor (i use notepad++), scroll down till you see 2 entries named >
STEERLEFT=0,X_AXIS (LS),0.00,-1.00
STEERRIGHT=0,X_AXIS (LS),0.00,1.00
now the numbers on the end (1.00) are the sensitivity, 1.00 is default (oversteer) experiment with them, (i tried 2.00 but that caused to much understeer for me)
i settled on 1.75, note remember to hit save, problem solved 🙂
Edit: note there are STEERLEFT and STEERRIGHT entries for keyboard and xbox controller, be sure you edit the right ones