Realised to enter for the German GT Cars Championship, this wonderful and brutal 964 Carrera RS 3.8 (the race version is called RSR 3.8) is developed directly from Porsche factory and, with precision, at Weissach where race cars and prototypes are built.
Into details, the most evident esthetical modify is the big rear wind: it concerns a biplane element which is adjustable on six different positions; a higher angle of incidence means a higher level of "deportanza" , at a certain speed.
As concern the little front wind, at Porsche Factory have followed the technical solution of TechArt G.m.b.H., which consists in a little wind in connection with the front wheels. In the front part also two little air-intakes which take cold air to the additional oil-cooler have been added. The car have also the usual enlarged sides of the Turbo version.
The presence of an additional oil-cooler is not accidental, because the entire engine has been modified: now the pistons have a larger diameter (102 mm.), but the stroke is the same. So now there are 102 x 76,4 mm. of bore and stroke values for a 3746 cc. displacement value. Compression ratio has been a little reduced (from 11,3 : 1 to 11 : 1). There are also new rocker arms and new valves, which have a new profile. All the modifications of the engine have taken to a new feeding system: now there's a new Motronic, the 2.10, which administrates in a better way ignition and injection, and have also a knock-sensor. Every feeding duct has its own throttle. There is also a more sporting version of the usual air-filter which gives a little more power and gives to the engine a better sound. The exhaust system has been modified: now there are new exhaust pipes and two "three ways" catalysts for every "bancata" with Labda feeler. With these modifications, the RS can deliver 300 hp @ 6500 rpm. (in comparison with 250 hp @ 6100 of the RS 3600). At the same way, the torque has been increased from 31,6 kgm @ 4800 rpm. to 36.6 kgm @ 5250 rpm. The RSR is more powerful:  325 hp @ 6900 rpm.
In comparison with a normal RS, the RS 3800 weighs 1210 kg, that is 140 kg less. This result is due, most of all to the use of sheet-aluminium instead of the sheet-steel (doors and bonnet), and to the fact that side windows and rear windows are made with thin glass.
The suspensions, in co-operation with Bilstein, have been stiffened using coils and gas shock-absorbers with specific setting; there are also new anti-roll bars: the front one is adjustable on five different positions, the rear one on three different positions. In the front part there is also a dome bar, which gives to the front suspension a more firm and homogeneous handling, especially along the bends and during violent brakes. As all the cars prepared for races the 911 RS has a more essential cockpit in comparison with the street version: there aren't the electrical side windows, the electrical roof, the electrical seats, the power steering, the airbags. There are sport seats, the rear seats have been taken away and now there is a little shelf made with moquette with a "RS 3.8" logo. There are a smaller three spokes steering-wheel, the gearbox has a longer first and second gears, the clutch is the same of the other models, the steering-wheel has not the power steering.
There are also new tyres: now the RS "wears" enormous Dunlop SP Sport with the following dimensions: 235/40 ZR 18 front and 285/35 ZR 18 rear, fitted on new wheels:    9J x 18 in the front and 11J x 18 in the rear.
As concerns the performances, obviously wit such these modifications, they are smashing:   top acceleration 0-100 km/h in 4,9", top acceleration 0-200 km/h in 16,6", 274 km/h of maximum speed. Brakes are great: there's the extraordinary brake system of the Turbo version, with enormous (299/322 mm. diameter) discs and the ABS system,  which give to the RS an incredible brake power, as is the Porsche philosophy, of course.