As you and others have already pointed out, that G = gas guzzler, there are the practical considerations of the G vs F30. The Infiniti back seat and trunk are significantly smaller than the F30 and the G37 has no fold down rear seats, not even an option.

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2013 F30-335i M Sport, Glacier silver, 8 spd, black dakota w/walnut trim, premium pkg, 18" Style 400M wheels, adaptive M suspension, variable sport steering, M Sport brakes, front & Rear PDC, Sat radio, BMW Assist pkg.