Regular petrol has been E10 at my usual petrol station for a few weeks now. Bizarrely I think my mpg has improved a little bit, which doesn't make a lot of sense as the energy content of the fuel is supposed to be a bit lower. In any modern car you should only use 'Super' petrol if the car is designed to use it, it won't do any harm but it costs more and you don't get any performance benefit. Basically, whatever it says inside the flap and in the handbook is what you should use.