In respect of the term "mileage," I think that for a metric conversion it would probably be simplest to refer to it as a "fuel consumption rate" instead; I mean, we could go with something such as kilometrage, but it sounds too weird. Heh.
My uncle was trying to sell us some of these while we were there visiting.. He has many drivers that say they have seen much difference in their milage distance..
We didn't take any though... perhaps we should have tried them eh...