Audi has revealed a face-lifted version of its A4 saloon.The updated A4 will be a key rival to the recently revealed, sixth-generation BMW 3-series and the recently-updated Mercedes-Benz C-class. The reworked A4 gains a host of detailed styling and changes to its interior � all of which are aimed at setting it apart from the current model. Among the visual tweaks is a subtly altered front-end