Hi,Tempest is right it's not to good or not as good as Kia would have you believe.I do not drive slow with mine and it's got better,I am getting 45-48mpg with 8.5k on the clock.If you put the aircon on it takes it down a little but I suspect that if you are going to take it easy then 50mpg will be about the average.Don't have a problem with noise though tyre noise is present but I have Kankook tyres and I think these are slightly less noisey than some makes that Kia use.My car is the manual box with the diesel engine and even though I am having great problems getting it away from my wife I love the car.It's a car that seems to be more than just a car,you become very attached to it,it's great.I cannot recommend you to hit a brick with the 18" black wheels,I did that yesterday going round a roundabout ,someone had droppeda brickon the road.I have scuffed the edge of the wheel and the tyre,don't know if I have to replace the tyre yet but I hope not as I have just found out that it's rather expensive to replace.