I use bp 98, i usually get on average 12.3l/100km (manual calc). The dash reading is ALWAYS wrong, and funnily enough my fuel gauge only thinks there is 50 litres in the tank. I do get up to 13.6l/100 from time to time if im only doing like suburban driving (0-80, traffic light, 0-80 traffic light etc) . If the car is run on 91 it runs like crap, pings and uses more fuel