Hi Guys I've had a C5 110 sx diesel for 32000 miles so far and it has averaged 41/42mpg so I reckon its ok. Works out at around the gov figures of 8 to 9 pence per mile. I've reset the computer a few times before long journeys and its come back with some really good figures as you might expect, but I do a fair amount of round the city stuff as well. Running at under 70 on m/ways it will return impressive mileage but thats pretty boring. Just like any motor I guess you need to look at the overall average over time to get a real feel for it. Cheers Smithy