It seems like Audi has filled all the spaces left free in the categories of premium cars. Look at these spy photos taken from the site Carscoop. blogspot. com: Audi RS4 Avant shows struggling with the test on the Nurburgring circuit in Germany. The Audi RS4 Avant is a prototype based on the S4 Avant with a few changes: there are 20-inch alloy wheels, a modified front bumper, air intakes novel, innovative engine cooling system and muscular wheel arches.