I've used BP Ulitmate in both my pre-LCI and LCI 330d and found the car is far more responsive over normal diesel.
I tried a tank of V Power in my LCI just after I had it and found it made the car run like with normal diesel and felt no difference at all, couldnt wait to get rid of the tankful and get some BP Ultimate back in it.
To be honest, it doesnt make the car any quicker - I did some Dynolicous testing with both BP Ultimate and V Power and there was no difference in performance figures. But to me, the responsivness is definately there with Ultimate everytime you press the throttle and this for me adds to the enjoyment of driving the car.
Bottom line - if it made no difference then I wouldnt be paying the extra out on it. But you can tell the difference and normal diesel just makes the car run flat IMO.