After one month of ownership of my M5, I've spent $524.22 on gas. Granted I have driven quite a bit in the car but wow! this is a bit crazy!!! I find myself at the pump every other day with a 65 mile daily commute. Also, I rarely hit the M button and most of it is highway driving. I'm averaging 14.6 miles per gallon. But when it's all said and done, I still have a smile on my face from ear to ear. Plus it's worth all the thumbs up, waves, and honks I get....I think.