The volume and location of the two fuel tanks have been improved. They now hold 640 litres, up from 480 litres on the preceding model, are located in the rearward area and can be filled from the left- and right-hand sides. The advantage of the plastic wheel arches is that these exposed parts of the body are not damaged as easily and remain corrosion-free.

Many technical improvements and implementation of customer requests on the S 431 DT have been aimed at increasing comfort and service-friendliness and reducing possible harm to the environment. This includes improved accessibility for drivers and service staff in all vehicle areas. The spare wheel compartment and all tire-changing accessories are for instance located on the right side of the vehicle. The on-board kitchen features a new look and its modular layout includes all the usual options. The water consumption of the newly designed, easy-to-clean toilet has been reduced by 50 percent thanks to a high-pressure flushing system. The volume of the refrigerator at the front is 35 or 60 litres, depending on the version. The luggage compartment loading height has been reduced by 150 millimetres to 1 290 millimetres and the luggage compartment flap increased in width by 20 millimetres to 585 millimetres.