 By 1988, Beechcraft had begun work on the replacement for the 300, it was introduced in 1990 and initially marketed as the Super King Air 350.It has two extra cabin windows on each side and MTOW was increased again to ; as the same regulatory situation that led to the development of the 300LW still existed, that model continued to be produced until 1994.Like the 200 and B200 before it, a version with a large cargo door was developed, the Model B300C marketed as the "Super King Air 350C".