In 1999 a limited edition Diablo GT was introduced. Only 80 sold. This Diablo GT was a completely race-oriented model, with aggressive styling, lots of interior removed and of course a bigger engine.
The Diablo GT was noticeably different on the exterior. The Diablo GT had black carbon fiber front air dam with large brake ducts and a central vent for the oil cooler (the car still featured driving lamps, the single pair of round units featured on the Diablo VT Roadster). In the front luggage compartment lid, a large air extractor was added, while the small corner vents on the front fenders were changed to NACA style ducts. The engine lid featured a large central ram air duct protruding above the roof; a rear spoiler was standard equipment. This radical new body was composed mostly of carbon fiber, with the steel roof and aluminum doors being the only components to retain their standard material. Special 3-piece OZ wheels finished the GT’s exterior package.
While previous Diablos had tuned and tweaked the 5.7 L (348 cu in) engine with various ignition and fuel system upgrades, the Diablo GT opted for a larger-displacement alternative. While the basic V12 block remained the same, the engine was stroked from 80 mm (3.1 in) to 84 mm (3.3 in) for a new displacement of 6.0 L (366 cu in); this engine, which would later be used in the revised Diablo VT 6.0, produced (in GT trim) 583 PS (429 kW; 575 hp) and 630 N·m (465 lb·ft) of torque. The transmission was the same 5-speed used in other Diablos, but different gear ratios could be specified by the race-oriented buyer. Rear-wheel drive was used to save weight, as usual