strange really that you can get more from a bigger engine and more cylinders, I had a focus ST with the 300 pack on it, best i ever recorded was 24, ever, worst was 2, couldnt even get an SL55 AMG to read less than 4, my VR6 just with BMC and cat back gives about 27 average on the mfa if i drive a few 30 mile runs to a tank, it will go all the way up to 36 but most town duties returns below 20s on the mfa, i havent filled up and run to empty for ages, been running half tank or less at a time, last time i did i got 290 from full to empty, but my driving style is pretty much i like to overtake