Q: is it heavy on fuel 2.0 petrol
A: You'll find a review here, including the fuel consumption figures: http://www.carpages.co.uk/peugeot/307cc-review-part-1-14-01-05.asp It's quite a quick car as you'd expect for a 2.0 litre. If you drive it sensibly on the motorway (more difficult with a powerful car), you should get 40mpg. Anywhere else you'll be lucky to get 30, and you may even go lower.