As far as I know elite setting is recommended. Be sure to have the DampeningEnabled set at "0" under </DeviceList> <Flags in the vehicleset_pc_logitech_g27_separatepedals.xml file under ControllerDefaults\PC. If it is not you got to do the following:
-Sellect an other controller in the game assign the contols and then save
-Leave the game
-Under properties of the xml file you have to untick read only
-open the xml file in notepad++ and change the DampeningEnabled setting and save the xlm file
-Make the xlm file read only again
-start op the game, select G27 under controller and set it up
-save with the shift button and enter
-If you get an warning that the settings wil be overwritten you did it right. Press enter again and try it out
Its needed to reselect your controller this way or the xml file will not be read by the game.
Hope it works for you. Adjusting the xml file and the effects it may have is subject of debate. Some claim it solved their problems, others screem "placebo!!" For me I'm not sure yet

There are many accounts of people who tinkered with settings and claim it had a good effect on the handling, and just as many who say it did nothing for them. It's very much trial and error at least.
In the readme of the minimod are some settings for the G25. you might want to try them out.
Good luck