What kind of mileage are you getting in the Prizm now? Apply that same increase to the Echo, Focus, and Civic. Also, check what others are getting with their Echos, Focus' and Civics in the
ecomodder garage.
IMO it sounds like the Echo is the best bang for the buck, but its also the smallest car. If you don't need the extra space it is a great car capable of really good mileage.
Here are the EPA ratings for the cars.
