http://www.f1fanatic.co.uk/2010/03/05/w ... 010-video/
Shell reckon that the fuel rules will trigger the biggest changes in fuel composition for 15 years. Certainly there is a point that fuel will be much hotter on average as no colder fuel will be refilled. That requirers the fuel suppliers to pay more attention to volatility of components. They will use formulations that have higher stability at elevated temperatures. I allways thought that there are very narrow limits to tweak the fuel but this article says different.