Is it manual or auto?
I had an E90 manual with the 163 engine and that averaged (on the readout) 37mpg.
IN the same kind of use I now get from my 177 auto and average of 39mpg.
Those are REAL world figures, not the brochure and not from someone cruising up and down the m-ways...
Current - M-Benz C250Cdi Sport Plus Auto Est.
Previous - Alpina D3 BiTurbo E90 LCI Manual, 320d M Sport E92 Auto, 330i M Sport E92 courtesy of BMW UK....320i M Sport E92 Auto, 320d SE E90 Manual.