Depending on your driving style you will notice benefits. I have a 25mm RARB and 23mm FARB with coilovers, spacers, strut braces etc etc. In the dry the RARB helps to vastly reduce understeer and increase the sharpness and response of turn-in. However in wet, or low grip situations the back-end can try to come round too easily - I am going to try the middle setting on my RARB next time it is wet to combat this. It is normally set on stiffest, but the adjustable nature is definitely a bonus.