Car Auto Design

Air cooled - These vehicles used air as the cooling medium for the engines and thus the heat losses were substantial. The earliest 911's were of this type and the technology was used by Porsche till 1998. The cars built with this technology include Porsche 911 classic (1964-1989), Porsche 964 (1989-1993) and Porsche 993 (1993-1998) wide body.

I could only find one stat for the fuel economy of the Porsche 911 GT2. The GT2 has an 18.8-litre, per 100kms for city driving and 8.9-litre, per 100kms for highway driving. Not exactly your favourite green car to drive around in the city, but imagine most 911 GT2 owners couldn't care less.
All Original Porsche 911 GT2