Porsche 930 Turbo
Porsche badged the 930 simply as "Turbo" (although early U.S. units were badged as "Turbo Carrera") and debuted it at the Paris Auto Show in October 1974 before putting it on sale in the spring of 1975.
The 930 proved very fast but also very demanding. The 911 was prone to oversteer because of its rear engine layout and short wheelbase; combining those traits with the power of the turbocharged motor, which exhibited significant turbo-lag, meant driving the car required more skill to drive at the edge of its (higher) level of performance. Even though the rear engine layout provided superior traction, sudden bursts of power to the rear wheels in mid-corner could break the tires loose, causing the car to literally spin out of control. This effect was amplified if an unexperienced driver would instinctively lift the throttle in reaction. The vehicle needed to be kept at high revs during spirited driving to minimise the turbo lag. Skilled drivers quickly learned how to drive the 930 properly, and with that knowledge came the ability to drive the car above and beyond the levels of most other sports cars. Nevertheless, some fatal accidents resulted in product liability law suits brought against Porsche in the US, where Ralph Nader had made his name criticizing the rear engine-rear wheel drive layout of the Chevrolet Corvair.
Porsche made its first and most significant upgrades to the 930 for 1978, enlarging the engine to 3.3 litres and adding an air-to-air intercooler. By cooling the pressurized air charge, the intercooler helped increase power output to 300 hp (DIN); the rear 'whale tail' spoiler was re-profiled and raised slightly to make room for the intercooler. Porsche also upgraded the brakes to units similar to those used on the 917 racecar.
Changing emissions regulations in Japan and the U.S. forced Porsche to withdraw the 930 from those markets in 1980. It remained, however, available in Canada. Believing the 928 would eventually replace the 911, Fuhrmann cut-back spending on the model, and it was not until Fuhrmann's resignation the company finally committed the financing to re-regulate the car.
Source: Wikipedia, 2011