I removed the swirl vanes myself using pmw blanks. The main reason is that the o rings on the vanes were leaking diesel down the side of the block. Very common, Ive seen a few like it. I thought if I am going to change the o rings I may as well get the blanks with them fitted.
I believe the car had less torque below 1800 rpm the fuel consumption dropped and the dpf started having issues. I then had to get rid of the dpf which has improved the car quite a bit. My car has 72k on it and the swirl vanes were like new. In fact I have kept them but I probably wont put them back, but Im not convinced it is a brilliant move. Of course if you take it all out as I have, it should work out ok,