Audi offers a choice of four V6 engines -- one gasoline-powered and three diesels -- for the A6 Allroad Quattro. The A6 Allroad only comes with automatic transmission. The gasoline-powered model and the two smaller diesels are equipped with a sporty 7-speed S-tronic transmission, and the biggest diesel with an eight-speed Tiptronic, optimized for fast shifting. We tested the performance of the 180 kilowatt diesel, which produced an impressive 580 Newton meters of torque.