The exterior of the BMW 321 Sedan differed only slightly from that of the previous model, the 320. The rear-hinged doors were the most easily recognisable attribute. Moreover, the company had now managed to compensate for the initial technical deficiencies beneath the metal dress. The loud engine noises had been reduced by means of slight modifications. However, adoption of the more stable front axle design used in the BMW 326 was much more important because it gave the car the same excellent driving characteristics as the larger model.