In 1933, BMW introduced the 303. Larger and more conventional than the AM-series 3/20, the 303 used BMW's new M78 engine, making it the first BMW automobile to use a straight-six engine. The 303 was also the first BMW to use the "kidney grille" that would become a characteristic of BMW styling. The 303 formed the basis for the four-cylinder 309 and the larger-engined 315 and 319, while the 303 chassis supported the 315/1 and 319/1 roadsters and the restyled 329