Porsche recently published an excellent short video highlighting Louise Piëch's very unique and important 1975 Carrera 2.7 Turbo.

This one-off Turbo was actually based on Porsche's top of the line model at the time: the Carrera 2.7 MFI (which was derived from the 1973 RS with the identical engine) and originally fitted with a 2.7-liter turbocharged engine. The Carrera 2.7 Turbo was built on a Carrera 2.7 chassis #911 560 0042, hence the narrow "SC style" flares from the typ "911 SC" Carrera 2.7 and the rear Carrera badging, and predated the first 930 Turbos which wouldn't be built until months later. The Turbo was presented to Louise Piëch as her 70th birthday present on August 28, 1974. The engine was estimated to produced approximately 240 PS and the Carrera 2.7 Turbo was also equipped with a 10,000 RPM tachometer.

This special Carrera will be covered in more detail in the Carrera MFI book.