Ah Extra, the Nissan Skyline GTR is a 'Group A' 'homogulation special' ***, made in very limited numbers with a 480HP (SAE) twin turbo/inter-cooled, 24 valve (4 valve per cylinder) DOHC 6 in-line engine & AWD (constant 4WD, with torque automatically distributed to all the wheels in the perfect balance to maximise traction, so if a wheel looses traction, more power is sent to the other 3 wheels, for a good nuetral/slight oversteer balance, the default setting was about 67% at the back & & 33% at the front), 4 wheel steering, multi-link independent suspension on all wheels & antilock breaks (which is no deal now, but when the GTR first came out over 12 years ago it was a big deal). The Skyline blitzed 'Group A', & this one one of the reasons the 'Group A' racing Series was replaced as the premier Touring Car class, by the '2 litre Tourers' (Such as the BTCC).
***Made in limited numbers to match the minimum specified number for a car to be consided a production car for a production racing series, so if a formula/class said that a minmum of say 200 or 1500 or whatever cars have to be made on the production line with the same/almost the same specs as the racing car, then those cars are referred to as a homogulation special, the Ford Seirra Cosworth was also a homgulation special for Group A racing, a formula where only a limited amount of modifications are allowed. So the manufacturers, would then put into production the bare minimum of cars specially modified so then those modds were legal on the track. For 'Group A' they had to make at least 1500 such cars for it to be considered a production car. The BMW M3 started out as a 'Group A' homogulation special too. BTW, there were a number of post-factory mods allowed under 'Group A' specs, so it wasnt a production racing series. Production car racing does exist, where the only mods allowed relate to brake pads, shockies, tyres (as long as they were street tyres), exhaust & safety equipment. The Ford Falcon GTHO Phase III was a production class homogulation special.