Interesting. My 09' Z06 gets 22mpg driving around town, and nearly 30 mpg on the highway. 7.0L (427ci).
My airport car (07 black Ford crown vic police interceptor) gets about 17 mpg.
If my soon to be bought M3 gets the same as the Ford, I won't care.
Someone suggested I look at the MB C63. Talk about a fuel hog, 10 mpg! No thanks!