I was assuming the use of a pre-DPF engine. I don't think I would risk running bio-D in a common rail engine - the tolerances are too tight and the room for error is too great. Consider that the secondary filters are now, what, 5 microns? 3? I forget. A set of injectors and a HP pump head would cost you about $4500 + labor.
Believe me, I have changed a few!