In spring 2004 (four years after the launch) Mercedes‑Benz significantly enhanced the successful C‑C lass in terms of engineering, equipment and design. With its advanced technology, good comfort on long journeys and sporty agility, the C‑Class of model series 203 had attracted more than 1.26 million drivers worldwide since 2000. Never before had Mercedes‑Benz sold so many vehicles from one model series in such a short time.
Following deep revision, the Stuttgart-based car brand had now reinforced the C‑Class's proven characteristics while setting new standards in dynamism, comfort and quality feel. The chassis, steering and six-speed manual transmission were given a sports tuning so that the C‑Class offered an even more agile driving experience.
In spring 2004 a 141 kW (192 hp) four-cylinder, supercharged engine was added to the range in the C 230 KOMPRESSOR. Thanks to the TWINPULSE system which combined various technologies such as a belt-driven supercharger, balancer shafts, intercooler, variable camshaft adjustment and a four-valve-per-cylinder design, the engine in the saloon consumed just 8.9 litres of premium petrol per 100 kilometres (NEDC combined cycle). The further developed C 220 CDI also proved to be powerful and economical with an engine which output 110 kW (150 hp) – 5 kW (7 hp) more than before.
In the shape of the new 270 kW (367 hp) C 55 AMG, which replaced the C 32 AMG, for the first time Mercedes‑Benz offered an eight-cylinder engine within this model series. The C 55 AMG accelerated from a standstill to 100 km/h in only 5.2 seconds, delivering a high level of sporty fun at the wheel with the standard AMG sports suspension, five-speed automatic transmission with steering wheel shift buttons and AMG SPEEDSHIFT. This top-of-the-range model outwardly differed from other C‑Class models due to a distinctive front-end design featuring elliptical twin headlamps and a front end extended by some 80 millimetres to accommodate the powerful V8 engine. Through their individual design, the side skirts, boot lid and rear bumper also emphasised the high-performance nature of the eight-cylinder version.
The interior was further upgraded with a new cockpit design including sophisticated controls and THERMATIC automatic climate control as standard. By applying the utmost care and attention to detail, the designers at Mercedes‑B enz were able to enhance the C‑Class's interior. Evidence included understated chrome trim on various dashboard controls, as well as redesigned switches and modified seats for improved comfort. Round dials in the style of high-quality chronometers formed the centrepiece of the completely redesigned cockpit. Information appeared on a vertical central display between the speedometer and rev counter which corresponded with the keys on the multifunction steering wheel and enabled multiple settings to be adjusted. The form and function of the air-conditioning operating panel were likewise improved: adjusting settings was easier thanks to large control knobs, which helped to further enhance the interior's quality feel.
A more dynamic exterior appearance came courtesy in particular of the redesigned front bumper with its striking, sports car-like lower air intake and the equally new radiator grille, which looked wider with three louvres and therefore more powerful. Depending on the model and equipment, the louvres were either painted or perforated for a sporty look.
The headlamps on the Mercedes‑B enz C‑Class now featured a clear glass look as standard. New, more scratch-resistant paintwork based on nanotechnology also became part of the C‑Class's standard equipment package. Bi-xenon headlamps with cornering light function, steering wheel shift buttons for the automatic transmission and new audio and navigation systems rounded off the high-tech optional extras.
The newly developed cornering light function in particular was Mercedes‑Benz's way of underlining its claim to technology leadership in this market segment. A combination of bright bi-xenon headlamps and the special cornering light function was integrated into the front fog lamps for the first time, thereby illuminating the area next to and in front of the vehicle at a wide angle. This was intended to make it easier to see pedestrians and cyclists when cornering and to improve visibility on tight bends.
The track width was increased from 1493 to 1505 millimetres with 16‑inch wheels as standard and wide 205/55 R 16 tyres strengthening the C‑Class's dynamic look. In addition, the CLASSIC and ELEGANCE lines were given the more sporty side sill panels and rear bumper of the AVANTGARDE model. Various technical modifications were made to the chassis, steering and manual transmission of the C‑Class for even more superlative driving dynamics. This package of measures named DIRECT CONTROL included newly developed bearings on the front and rear axles, a more direct steering ratio and a reinforced stabiliser on the rear axle. The result was more agile cornering without sacrificing comfort.
The ease of operation and high-precision shifting of the standard six-speed manual transmission were impressive. On the C 320 and models with the sports package/AMG sports package, Mercedes‑Benz included a sporty transmission with significantly shorter shift travel than before.
As of summer 2005 four new engine variants were added to the line-up for model series 203: the new six-cylinder C 320 CDI diesel version featuring third-generation common rail technology and particulate filter as standard outdid the previous in-line, five-cylinder engine (125 kW/170 hp) by 32 percent on output and more than 27 percent on torque. Mercedes‑Benz supplied the C 320 CDI as a saloon or an estate. For the petrol models, advanced six-cylinder technology was available in three categories for the first time from mid-2005: the C 230 (150 kW/204 hp), C 280 (170 kW/231 hp) and C 350, the latter some significant way ahead of similar engines by having a V6 unit capable of generating an output of 200 kW (272 hp) and 350 newton metres of torque. Deploying these new six-cylinder engines reduced petrol consumption by up to 13 percent compared to predecessors.
Mercedes‑Benz customers were able to purchase the C 230 for the price of the previous four-cylinder model, the C 230 KOMPRESSOR. The new C 280 was also provided at the same price as the previous C 240. As standard, the C 350 was combined with the ELEGANCE or AVANTGARDE line and boasted 17‑inch alloy wheels. The new, top-of-the-range V6 model in the C‑Class was therefore more affordable than the previous C 320 of a comparable specification. Also new for the summer of 2005 were the C 280 4MATIC and C 350 4MATIC models with the permanent all-wheel drive system 4MATIC. They delivered up to 45 kW (61 hp) more output compared to previous models.
As an option, the unique seven-speed automatic transmission 7G‑TRONIC could be selected for the V6 C‑Class models. This complemented the engines' pulling power and in-gear acceleration to perfection. 4MATIC variants were equipped with a five-speed automatic transmission as standard.
The C‑Class's comprehensive standard equipment now included automatic climate control, a multifunction steering wheel, windowbags, crash-responsive NECK-PRO head restraints for the driver and passenger (in the saloon and estate versions), as well as more scratch-resistant paintwork based on nanotechnology. In addition to the individual CLASSIC, ELEGANCE and AVANTGARDE equipment lines, Mercedes‑Benz now offered two sports packages as options, which reinforced the sporty and dynamic nature of the C‑Class even more.
Production of the C‑Class Saloon, model series W 203, in Sindelfingen ceased on 14 December 2006, while the last W 203 left Bremen a few weeks later on 1 March 2007. By September 2006, Mercedes‑Benz had delivered two million C‑Class vehicles from model series 203 in three different body styles. With sales of more than 1.4 million vehicles, the saloon accounted for most of this success and helped to make model series 203 the bestselling Mercedes‑Benz passenger car.