search function is your friend. use it next time before asking questions that can take seconds to find the answer to.
the e is the "ETA" model. built for gas mileage. even though it won't get your 32mpg claim. the "i" motors have more horsepower, obviously they use more fuel.
different years and models have different gearing. on top of the 325i already gettign less gas mileage, you have a vert .. which makes the gas mileage worse than a coupe or sedan.