In my Suzuki Grand Vitara 2.0TD I used Millers (used to be called sport but now it is called Diesel Power Eco Max). Gives about 10 tanks per bottle. It did run smoother and quiter with a little more mpg. 39 up to 43 or thereabouts. A friend in motorsport raved about BP ultimate, I used this and for about the same price penalty as Millers got slightly better results. Less messy as no mixing or bottles to leak in the boot (the new Millers bottle is rubbish), and its factory mixed and tested. I'd favour the BP Ultimate. (Smoke test on MOT improved dramatically.)
