Audi natural gas models combine ecology and economy: The Audi A4 Avant g-tron2 and A5 Sportback g-tron3 feature a new, sporty design and a state-of-the-art touch operating concept. Customers in Germany can order both models starting November 21 – the Audi A4 Avant 40 g-tron at a base price of EUR 43,200 and the Audi A5 Sportback 40 g-tron for EUR 45,100.