So, how much more E10 than E5 does anyone use for the same mileage? I read on other car forums that owners are using more. Anyone got an idea how much more an NSX uses? (no, I haven't tried it myself).

If you have to use 5% more fuel, does it amount to producing 5% more carbon? Is the equation that simple? If so where's the advantage? Use more than 5% means it's worse for the environment!!! I suspect E10 fuel just ticks a box for the Green Party. Also much more tax for the government.

E5 (Super unleaded) is about 5% more expensive (at my local Sainsburys), so on the basis of using more than 5% of E10, it's cheaper for me to run E5!

Opinions?