I've been doing a mpg test sith various fuels and millers sport additive.
My car is a completely standard 130bhp A4 Sport (6), tyre pressures 34psi all round
For anyone who's interested I though it might be good to pass on my results so far.
Fuel type/miles acheived/range left/millers additive
Tesco - / 530/ 45 range/ millers
BP Ultimate - / 578/ 35 range/ millers
Shell extra - / 510/ 100 range/ no millers
shell v-power / 577/ 45 range/ no millers
now testing V-Power with millers added!