The new Audi A4 is still as fresh as the Prince of Bel-Air, but Audi had to bring something absolutely new at the Frankfurt Motor Show to share the stand with the e-tron.

These novelties came in the shape of two Audi A4 models with special engine features, both aimed one way or another at reducing fuel consumption and, even more so, fuel costs for the car’s user.

It’s all about the gas&l…