My avg for the first tank was 43/44MPG in my 330d and now on the current tank at about 38.6 MPG, But been exploring the power on this tank and more town driving so very pleased so far..
My 3.0 Z4 is at 26MPG avg and the best I have seen was 34/35MPG on long trip to London driving like a saint
So over the moon with the fact the 330D is just as fast once rolling and not driving it slowly is doing at least 10 - 12MPG more
Rob