We have a 2011 X3 35i Sportline, no ASS and no Eco-Pro mode. This is my wife's car, and I don't normally check mileage. On a solo trip yesterday, I drove about 150 miles in Normal mode on Interstates and averaged 70 mph and 29 mpg according to the trip computer (I reset that at the start of the trip).
2013 335i xDrive, Mineral Grey, Sportline, Black/Red leather, Dynamic Handling, Sport AT, Performance Tires, Increased Top Speed, Premium Pkg, Cold Weather Pkg, HK audio
2011 X3 35i, Titanium Silver, Black Nevada, Fineline Wave Wood, Premium, Technology, Cold Weather, Dynamic Handling, Sport Activity, 19" wheels, Premium Hi-Fi, Sat Radio
2008 535Xi retired