I did just that.....see one of my old threads. Chopped off the pipe at a 45 degree angle in the air box and the flap that goes across the intake pipe by the grille. Did not notice any diff on fuel consumption and only a slight difference in throttle responce at the lowest revs before the turbo starts boosting (CRD). Was an interesting experiment but not a lot was gained.....although it has a very slightly louder intake noise.
“You know, a lot of people buy horsepower, when what they really want is torque!”