It's how you drive brother. I've been with a friend in a Pug 207 1.4 petrol. And the way he was driving, he was regularly dipping to 22 litres / 100 kms (that makes 4.5 kms / litre) of course, he was doing it for fun, but it shows that if you drive like a fruitcake, you'll be disappointed with the fuel mileage.
BTW, the Honda R18A in the new VTi 1.8 works as an Atkinson / Miller cycle engine at low loads. But since we never use it at low loads, you never see it working in that zone. Thus no fuel savings.