A supercar (500+hp) that gets over 23 mpg surely must run on some super exotic fuel. And, yes, we're aware that in normal cars 23 mpg is shite, but for a car in this class it's really something.
Think Honda can do it?
Now before you 'vetties get up in a tizzy, we're aware that the Corvette Z06 generates 505hp gets 26 mpg on the highway. It's very, very impressive. However, the Z06 is only rated for 16 in the city... still, pretty impressive. Go GM!