From spring 2000 the SLK continued its success story with an even sportier look and new technology on board. Mercedes‑Benz also significantly upgraded the roadster's equipment and added innovations such as the Electronic Stability Program (ESP®), a six-speed manual transmission and cruise control with SPEEDTRONIC to the standard features. The new top-of-the-line V6 SLK 320 model was also fitted as standard with air conditioning.
The design modifications introduced with the new model year were apparent at first glance: new-design front and rear bumpers with integrated spoiler edges and reshaped side skirts reinforced the roadster's sporty attributes and created an even more powerful look. All of the add-on parts and the door handles were painted in vehicle colour, giving the impression that the body had been created in a single casting. The choice of paint finishes had now increased from eight to ten. New tail lights, stainless steel tailpipe trim and a painted radiator grille were further features of the new SLK design. As on other Mercedes‑Benz models, the side indicators were now incorporated in the mirror housings. There was also a new design for the boot lid handle with its integral lock.
The interior of the SLK was upgraded too: in place of the previous carbon fibre look, the centre console and door openers were now trimmed with high-quality, textured aluminium. As an option the interior could be trimmed with fine wood, for example brown eucalyptus with the attractive name "calyptus linea" or black bird's-eye maple. The innovative colour scheme, which offered SLK customers plenty of scope for individuality, was perfectly on-trend. Depending on whether fabric or leather appointments were fitted, there were up to five interior colours to choose from: anthracite, merlin blue, siam beige, magma red and lotus yellow. The powerful colours featured on the glove compartment lid, the central area of the door panels, the seat cushions, the instrument cluster surround, the edges of the centre console, the lid of the stowage compartment between the driver and passenger seats, the shift lever and its leather gaiter and the upper, inner edges of the new-design four-spoke steering wheel.
Other details which upgraded the interior of the SLK in both visual and practical terms included the new leather or wood highlights in the steering wheel and shift lever, the modified instrument cluster with its larger ASSYST display (Active Service System) and the new-design, ergonomically enhanced sports seats, which were available in an electrically adjustable version as an option. The new steering wheel (diameter 380 millimetres) had narrower spokes than previously and the entire airbag section could now be used to activate the horn. The sports seats had been stylistically and ergonomically revised and offered even better lateral support. Electric seat adjustment was now also available as an option. Other new features included stainless steel door sill panels, emblazoned with "SLK" on the four-cylinder models and with "V6" on the SLK 320.
Customers were able to choose between improved four-cylinder powerplants and, for the first time, a powerful six-cylinder engine with a 3.2-litre displacement. Even the SLK 200 KOMPRESSOR, the new entry-level model, delivered an impressive 120 kW (163 hp). It replaced the non-supercharged SLK 200 and the previous 2.0-litre supercharged model which had been available in some European countries. The supercharger made its presence felt even at low engine speeds – the engine delivered its impressive maximum torque of 230 newton metres from as low as 2500 rpm and it remained constant to 4800 rpm. Thanks to the supercharging, the SLK 200 KOMPRESSOR accelerated from 0 to 100 km/h in just 8.2 seconds and achieved a top speed of 223 km/h. Its fuel consumption was 9.8 litres per 100 kilometres.
The facelifted version of the SLK 230 KOMPRESSOR had an output of 145 kW (197 hp) – compared with the previous 142 kW (193 hp) – and developed an exemplary 280 newton metres of torque from 2500 rpm. The increase in output ensured even better performance: the SLK 230 KOMPRESSOR took just 7.2 seconds to accelerate from 0 to 100 km/h and achieved a top speed of 240 km/h. Fuel consumption was 9.8 litres per 100 kilometres.
The two four-cylinder engines had been totally overhauled and readied for future European Union emission restrictions. As a result, from the start of series production the SLK 200 KOMPRESSOR and SLK 230 KOMPRESSOR already complied with the strict EU4 limits – limits which were not due to come into force throughout Europe until 2005. Technical changes to the four-cylinder engines included the modified cylinder head with optimum flow to the inlet and outlet ducts for enhanced combustion chamber utilisation, the powerful single-spark ignition coils, integrated in the cylinder head, the new electronic engine management system, the noise-optimised, efficiency-optimised supercharger and the exhaust gas system with air gap-insulated exhaust manifold.
The cutting-edge V6 engine, introduced at the same time as the facelift, was just as low on emissions as the two four-cylinder engines. The engine had been demonstrating its strengths for some time in the E-Class, the M-Class, the SL-Class, the S‑Class and the CLK. With three valves per cylinder, dual ignition, low-friction cylinder liners and cutting-edge lightweight materials, the six-cylinder powerplant was among the most innovative engines in its class. In the SLK 320 it had an output of 160 kW (218 hp) and, with a maximum torque of 310 newton metres available between 3000 and 4600 rpm, ensured effortlessly superior power delivery and impressive performance: the V6 roadster accelerated from 0 to 100 km/h in 6.9 seconds and achieved a top speed of 245 km/h. Petrol consumption was 11.1 litres of premium unleaded per 100 kilometres.
The engine and exhaust system of all SLK models was continuously monitored by an on-board diagnosis system. It complied with the EU4 directive and informed the driver via a "Check engine" light in the instrument cluster if any component which was relevant to emissions was damaged.
From spring 2000 all SLK models were also fitted as standard with the newly developed six-speed manual transmission, which offered the short-throw gearshifts and low shifting effort typical of a sports car. Unlike in the saloons and estates of other Mercedes‑Benz model series, the sixth gear of the SLK transmission was a genuine top gear in which the roadster reached its top speed. The cutting-edge five-speed automatic transmission continued to be available for the SLK as an option. It now featured handy Touchshift control, which made it easy to select gears one to five manually in "D" mode. Xenon headlamps with dynamic range adjustment were also now available as an option. And to increase the range of the two-seater, all facelifted SLK models were equipped with a 60-litre fuel tank (previously 53 litres).
When it came to chassis technology, the key change for the model year 2000 Mercedes-Benz SLK was the standard use of the Electronic Stability Program (ESP®). ESP® kept the roadster safely on course in critical situations and significantly reduced the risk of skidding. In addition the torsion-bar stabiliser at the front axle was reinforced and the rear axle was fitted with an additional torsion-bar stabiliser to improve handling still further. By using retuned shock absorbers, spring travel was reduced by 5 mm and the body was lowered in the interests of improved dynamics and a sporty look. The new SLK 320's impressive performance demanded larger and thicker front brake discs (diameter 300 millimetres, thickness 28 millimetres). At the rear axle the SLK 320's brake system was identical in size to that of the two supercharged models (diameter 278 millimetres, thickness 9 millimetres).
To ensure that the vehicle's crash safety in a serious offset frontal collision complied with NCAP requirements, the side members and main floor assembly were reinforced, the thickness of the rigid ellipsoid bulkhead was increased and additional securing points were added to the transmission crossbeam. Special impact absorbers at the front ends of the side members supported the wheel in an offset collision so that the impact forces were dispersed into the side structure of the body in a controlled way. A change to the contours of the inner door panel and additional reinforcements in the beltline area ensured that the doors of the SLK were also able to transmit higher forces into the body structure; these were supported by solid B-pillars and reinforced elements in the side wall panelling. A newly developed pendulum support between the console of the shock absorber tower and the brake master cylinder reduced the backwards movement of the brake pedal in an offset crash. These measures improved the body rigidity of the SLK yet again, ensuring even better handling and even higher long-term quality.
Large crumple zones were available at the rear of the roadster too. Here the engineers developed linkages between the rear longitudinal members and the supporting structure in the floor and in the sides of the SLK's body. The forked structure ensures that, in the event of a rear collision, the impact forces are dispersed evenly.
Taken together, the measures ensured that the SLK offered the greatest possible occupant safety – even in a side impact, where the passengers could rely on a sturdy body structure and standard-fit sidebags in the doors.
All model variants of the Mercedes roadster were fitted as standard with light-alloy wheels. They differed, however, in size and design: while the SLK 200 KOMPRESSOR left the assembly plant with size 7 J x 15 seven-hole rims with a high-sheen finish and size 205/60‑15 tyres, the SLK 230 KOMPRESSOR was fitted as standard with size 205/55‑16 tyres at the front and 225/50‑16 at the rear, on high-sheen, size 7 J x 16 and 8 J x 16 six-spoke rims. For the top-of-the-line SLK 320 model the Mercedes‑Benz engineers used size 7 J x 16 (front) and 8 J x 16 (rear) rims with a sporty, five-spoke design. The tyre sizes were identical to those for the SLK 230 KOMPRESSOR. Customers who purchased the supercharged models could select the V6 roadster's wheels as an option. And the SLK 230 KOMPRESSOR model's rim and tyre combinations were also available as an option for the SLK 200 KOMPRESSOR. The roadster looked even more dynamic with 17‑inch rims, available as an optional extra either in a sporty AMG design or an attractive seven-spoke look.
In November 2000 the company presented the SLK 32 AMG. With its 260 kW (354 hp) AMG V6 supercharged engine, it adopted a leading position in this segment from spring 2001. This was underlined by the technical data: top speed 250 km/h (electronically controlled), acceleration from 0 to 100 km/h in 5.2 seconds, maximum torque of 450 newton metres at 4400 rpm. Despite this, fuel consumption (11.2 litres of premium unleaded petrol per 100 kilometres) was still respectable and the engine complied with the EU4 emissions standard. It was based on the SLK 320's V6 engine, but had been fundamentally modified with, among other things, a new crankshaft with adapted bearings, new connecting rods, pistons in a high-temperature material, a new balancer shaft, a lightweight camshaft, harder valve springs and an oil pump with a higher flow rate. The power was passed to the rear wheels via a five-speed automatic transmission with special sporty tuning. Optimisation measures also included a new charge-air cooler with a highly efficient air/water heat exchanger system. This offered high compensation and balanced out temperature highs, ensuring that the full output range of the SLK 32 AMG was always available. The exhaust system, apart from the intake manifold, was tuned to the modified technical conditions. One intentional side-effect was a subtly throaty engine sound.
The SLK 32 AMG's chassis and suspension set-up was adapted to the engine output. In addition to a modified spring/damper tuning, a wider rear axle track and a larger torsion bar at the front axle, the brakes with their impressive deceleration performance (approx. 10.5 m/s2) were a particular highlight. The system featured internally ventilated disc brakes all round (334 millimetre diameter at the front, 300 millimetres at the rear), an anti-lock braking system, Brake Assist (BAS), ESP® and integrated ASR. The 17-inch AMG twin-spoke light-alloy wheels with their sterling silver finish were a completely new development. In addition to the impressive look, they optimised cooling of the fade-resistant disc brakes.
The body of the SLK 32 AMG was styled to create an independent look. There were new-design front and rear aprons, coordinating side skirts and a subtly integrated airflow break-away edge on the boot lid which reduced lift at the rear axle by over 50 percent. The AMG styling continued inside the vehicle. Sports seats with integral head restraints, specially developed for the roadster, provided firm lateral support and, as a result of the balanced ergonomics, were pleasantly comfortable on long journeys. The seats and door panels were trimmed in two-tone leather as standard. This material was also found on the firm-grip AMG steering wheel and the shift lever knob, while the centre console was trimmed in dark bird's-eye maple. The instrument dials in the SLK 32 AMG were silver-coloured. The speedometer went up to 300 km/h, and the speed was shown for the first time in steps of 30 km/h.
Shortly before model series 170 was discontinued, Mercedes‑Benz offered the "Final Edition", available from March 2003. Distinguishing external features included a radiator grille with a chrome silver-coloured metallic paint finish, high-sheen polished aluminium strips on the A-pillars, a chromed boot lid handle and "Final Edition" logos on the front wings. Rounding off the picture were 16-inch five-twin-spoke light-alloy rims.
The sumptuous interior of the "Final Edition" featured new-design sports seats, upholstered in soft black or classic red nappa leather, according to choice. The same natural material was also used to trim the centre sections of the door panels and the roll-over bars. Velour mats, their edges whip-stitched in chrome or red to match the interior appointments, were a further highlight. For the centre console, shift gate and door handles the designers developed decorative trim in high-sheen brushed aluminium. The instrument cluster differed from that in the standard SLK roadster by dint of its silver-printed dials and metal-coloured knobs for the clock and the trip odometer.
In spring 2004, just under eight years after its premiere and four years after the launch of the facelifted variants, the first-generation SLK was superseded by the completely redeveloped model series 171 roadsters. With a total of 311,222 units sold, the first SLK marked the opening chapter in a success story which the successor models seamlessly followed. The most popular model had been the SLK 230 KOMPRESSOR, with 113,520 units built.