The limited edition Diablo GT not exclusive or extreme enough for you? The most famous Italian supercar manufacturer not to have a significant racing heritage decided that the GT needed a race-only analogue, and so the even more limited production GTR was created. Constructed to race in Lamborghini’s Diablo Supertrophy one-make series, the GTR starts with a standard 6-liter GT car, and the modification list then becomes rather extensive. The highlights mainly center around chassis, suspension, and ancillary system improvements (like better cooling and braking systems), but the engine does get a revised exhaust system that boosts output to 590 horsepower. While doing without the AWD system found on the VT and other models, the GTR stays glued to the pavement thanks to a huge rear wing to provide downforce at high speeds. To save weight, the body is primarily carbon fiber and the wheels are made of a lightweight magnesium alloy. Despite the intimidating nature of the GTR, it’s actually a sweetheart on the track, easy to control at the limit and very, very fast. Don’t expect to see one at your local track day, however, as only 40 were built, making this a standout among the long list of amazing but rare cars found in Forza 4.