The blue motion series are indeed very economic with diesel.
My m8 has a VW van the T5 weighing in 2.3 metric ton with his gear in it he needs for his job and gets 16 kilometers or 10 miles a litre out of the 2.5 TDI 5 cilinder engine with 205 H.P.

Most small pertol cars here do 19 to 23 km's on 1 litre of fuel ( petrol) the 1.3 TDI engines in diesel get 33 km on 1 liter diesel.
Still delivering good H.P. and speed though.
But then we pay road tax and high taxed fuel as well, but have an very good road system of high quality.