Infiniti Q40 by Dinkun Chen - CC-BY-SA-4.0 The Infiniti Q40, once known as the G Sedan, is a car that brought extreme innovation to the luxury sedan branch of the automobile world. Those interested in purchasing this vehicle should perform proper research to ensure they make the right choice. What is the most reliable Infiniti Q40 year? Are there any that should be avoided at all costs? If you’re interested in purchasing the best Infiniti Q40 on the market, you’ve come to the right place.