Although BMW hasn't exactly been stingy with the details of the new i8 up until now, the Frankfurt Auto Show served as the venue for the car's official debut. BMW is calling it "the most progressive sportscar", and its radical design is meant to convey just how futuristic BMW sees the car as being. Originally seeing life as the Vision EfficientDynamics concept, there have been some changes, although fewer than we expected, to the current concept.

Most significant is that the 1.5-liter diesel engine has been replaced by a gasoline engine with the same displacement. This allows for 80mpg for the fuel economy, although the rating in the US would likely be lower. Power is rated at 349hp for the hybrid, and 62mph can be reached in just 4.6 seconds and should return 78mpg on the European cycle. It also features what BMW calls LifeDrive architecture, which involves both passenger seating and its propulsion system being based on state-of-the-art methods of cutting weight. The concept is constructed a carbon-fiber-reinforced plastic monocoque.

This is able to offset the weight stemming from the heavy electric drive components. It also features something called PRO ECO mode, a setting that allows the driver to utilize the most energy efficient method when traveling. This is done through a combination of braking, acceleration, and other electronics. Production is slated to begin in 2013, although we're expecting to see a few more changes before then. Specifically, the extra glass extending towards the bottom of the doors will be replaced with a more structurally solid material. Overall, BMW is serious about the i8 being able to handle various weather situations.

It's reportedly been tested in cold weather around the Arctic Circle. Whether owners will actually consider such a trip to one of the planet's most extreme weather climates is another issue, but the fact is that BMW wants the i8 to be an everyday fuel efficient supercar. Photos courtesy of Bmwblog.