Spring effect and Centering spring forces are two separate things. The centering spring (bottom slider) is for centering the wheel. It was suggested in the past to leave it checked but turn the slider to 0. I think it was a bug in the Logitech drivers and version 4.60 fixed it. So, no need for it to be checked anymore. The spring effect has something to do with the actual force feedback. Not sure exactly what it does, may have read it is a setting for canned effects on other games, but I do have the damper set way up. I get kind of a force feedback lag where I don't feel the car getting loose (oversteer) until it is too late to recover. Now I can feel it first before my sight reacts to seeing it. There have been plenty of arguements on RSC about these settings. Some swear by everything 0 except the overall force at 100% and others have argued about changing the damping to over 100% because of what I said about mine.