The black coupe seen here looks almost indistinguishable from the third-generation TT S coupe. Were it not for the previous-generation TT RS coupe (grey, bottom) tagging along close behind, our spies may not have twigged about this coupe's true nature.
The mule pictured here rides on 20-inch alloy wheels fitted with Pirelli tyres, with 255/30 rubber used at the front. Hiding behind the front pair of 20-inch rims are cross-drilled brakes with calipers that have been painted black.
Extra cooling equipment seems to have been tucked in behind the side air intakes in the front bumper. Our spies say that one of the car's rear dampers had an RS sticker on it.
Last year, Markus Siewart, a technical project manager at Audi, confirmed to Car Advice that the new TT RS will feature a turbocharged five-cylinder engine displacing no less than 2.5 litres.
Current indications are that the new TT RS will go on sale, at least overseas, in 2016. Expect it to sport a bunch of exterior styling tweaks to help differentiate it from other TT models.
Although we don't know many specifics regarding the TT RS' engine, it's probably safe to assume that it will generate more than 228kW/380Nm served up by the current-generation TT S' 2.0-litre turbocharged four-cylinder motor.
It will also likely exceed the 265kW/465Nm provided by the 2.5-litre turbo five-cylinder used in the previous-generation RS.