I find it weird that there is a very clear cut line between people who use optimax and people who will only use 95ron. Both will tell you they are correct. Ok on paper it is better but they always come back with "was no such thing as optimax when the cossie or rst came out!". personally i stand on the optimax side of the fence. Maybe its the cost ? but i like to think that using a better fuel your getting a better burn and there4 roughly evening itself out.