My previous car, a Grand C-Max 1.6 TDCI 11 reg, which I had since it was 11 months old, had no end of issues with the sensors in the EGR, dealt with under warranty (so without much explanation from the dealer as to what was wrong), and an EGR replacement, doubled up with sudden losses of power at certain points. However, two years ago I started using just Shell V-Power Nitro+ following your advice, and it hasn't missed a beat since.

Now I have just received my A6 Avant SE Executive on 17" tyres, part-exchanged my old car. The car arrived with half a tank, which I used, and then today I filled it with Shell V-Power Nitro+ diesel from the local garage, which I intend to do henceforth. The car's driving modes can be selected, between, Efficiency, Comfort, Auto, Dynamic, and Individual. Which of them would give me the best fuel consumption to offset part of the extra cost of the better diesel?