Just a clarification note:
5 US qts to 1 Imp Gal is a rough estimate but not acurate if you are past the decimal point.
42.8 Imperial MPG = 35.64 US MPG = 6.60 Litres/100km
I've also seen the figure of 6.8 L/100km which converts to:
34.59 US MPG
41.54 Imp MPG
Either way, these figures are nice and from what I've read, real world testing appears to suggest that they might actually be achievable in "restrained" personal use, unlike EPA ratings for most.