Choosing between petrol and diesel Territory

We aren't aware of any websites that list the real world fuel economy of cars, and we'd be reluctant to give you any figures as they might not apply to your situation in any case. Working out the time required to recoup the extra cost of the diesel engine is difficult because it depends on the cost of both petrol and diesel at any given time and the relative reduction in fuel consumption from using diesel. Based on your annual mileage, and the fact that it is predominantly suburban, I would suggest petrol as the way to go. If you were doing a lot of highway driving, and a lot of towing, then diesel could be a better bet for you.