Audi unveiled quite a few TT concepts at Austria’s Wörthersee show through the years, including the Ultra Quattro concept in 2013. In this instance, ultra can be attributed to the extensive weight reduction Audi performed on the otherwise 3,600-pound (1,633-kilogram) coupe. By changing everything from body panels to engine components and even nuts and bolts, Audi dropped the TT to just 2,450 lbs. (1,111 kg) while also increasing engine output to 306 horsepower (228 kilowatts).