The 2012 Infiniti G37 is available as a 4-door, 5-seat sedan. Starting at $37,800, the 2012 Infiniti G37 Base (A7) Coupe is powered by a 3.7L, 6-cylinder engine mated to an automatic transmission that returns an EPA estimated 19-mpg in the city and 27-mpg on the highway. The top of the line 2012 Infiniti G37 Sport (M6) Convertible, priced at $51,300, is powered by a 3.7L, 6-cylinder engine mated to a manual transmission that returns an EPA estimated 16-mpg in the city and 24-mpg on the highway.