The 2002 Infiniti G20 is a 4-door, 5-seat Sedan, available in 2 trims, ranging from the (M5) to the (A4). Upon introduction, the $21,395 (M5) is equipped with a standard 2.0L, 4-cylinder, engine that achieves 24-mpg in the city and 31-mpg on the highway. a Manual transmission is standard. The $22,195 (A4) is equipped with a standard 2.0L, 4-cylinder, engine that achieves 23-mpg in the city and 30-mpg on the highway. an Automatic transmission is standard.