The
Ultimate Aero TT is currently the worlds fastest comercially available "street legal" car on the planet. It holds the record for the highest top speed of a production car at 412 km/h (256 mph)
While the basic Aero model is about $240k; the Ultimate Aero costs well over $650,000.
EDIT:
Oh wait, the title say Miles Per GALLON, thought it said Miles Per HOUR...
It's funny, in the 1920's the ford Model T got 25 miles per gallon. Today a Ford Explorer gets 18...
I also found
this sort of interesting too.
Meh, oh well.