Based on the Porsche 911, the Group C Turbo Ruf was built for the 1987 model year using Porsche’s 3.2L flat-six engine. Modifications included lightened bodywork, improved brakes and suspension, as well as work to the aerodynamics of the car and to the engine. The car was seam welded and featured an integrated roll cage, improving chassis rigidity as well as driver safety.
The enginework done was extensive. The engine was enlarged to 3367cc and used a Bosch Motronic fuel injection system that was originally designed for the Prosche 962 racer. The engine was given twin turbos along with twin intercoolers and was highly tuned to make a whopping 469hp and 408 lb-ft of torque. Ruf built their own custom 5-speed transmission for use on the CTR after the options from Porsche didn’t meet their standards. Due to the lightened body panels and other considerations the car only weighed 2,580 pounds, making it an extremely quick car.
The CTR took only 3.7 seconds to get from 0-60mph and made it to 100mph in just 7.8s. Upon release, the Ruf CTR was the fastest car in the world, clocking in at 211 mph. Additionally the CTR outclassed most other supercars at the time, such as the Lamborghini Countach and the Ferrari Testarossa, while impressively having a higher top speed than the Porsche 959 and the Ferrari F40. The car also held the lap record at the Nürburgring-Nordschleife circuit, proving just how great it was on a track as well as in a straight line.
29 cars were built from scratch with work beginning in 1987, while more were converted from customer cars. Original pricing was $223,000 in 1987 (compared to at least $400,000 for the Ferrari F40). The CTR was succeeded by the CTR2 in 1995 and then more recently by the CTR3 in 2007, 20 years after the original Ruf CTR.
(Sources: Wikipedia, ruf-automobile.de)