The second-generation Mercedes-Benz SLK was already an unusual compact roadster with a folding metal roof. AMG then installed a 5.4-litre V8, creating a car with almost no direct rival. The story became stranger still when the SLK spawned the very first Black Series.
1. AMG put a large V8 into a genuinely small roadster
The R171 SLK was shorter than a contemporary family hatchback, yet the SLK55 AMG carried the 5,439cc M113 V8. Careful packaging created a long bonnet and tightly filled engine bay without turning the car into a front-heavy caricature. It remains one of the most extreme engine-to-car-size combinations Mercedes has sold.
2. The engine was naturally aspirated
Other AMG models of the period used the supercharged M113K, but the SLK55’s version breathed without forced induction. It produced 265kW—360PS—and approximately 510Nm in standard European form. Its appeal lies in immediate throttle response, V8 sound and torque rather than the huge supercharged shove of an E55 or SL55.
3. There was no manual gearbox
Every regular SLK55 AMG used an automatic transmission. AMG paired the V8 with the seven-speed 7G-Tronic-based Speedshift unit and steering-wheel controls. A manual might sound attractive to enthusiasts, but the automatic suited the broad torque delivery and helped the car switch between relaxed roadster and serious cross-country machine.
4. It could reach 100km/h in under five seconds
Mercedes quoted approximately 4.9 seconds for the 0–100km/h sprint, with top speed electronically limited to 250km/h in standard form. The figures were impressive, but the real novelty was accessing them with the roof folded away in a car that remained civilised enough for daily use.
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5. The roof gave it two distinct personalities
The R171 used Mercedes’ Vario-Roof, a folding metal roof that turned the SLK from enclosed coupé to open roadster. The generation also introduced features such as AIRSCARF, which directed warm air around occupants’ necks. The SLK55 therefore combined AMG performance with technology designed to extend the open-roof season.
6. It served as the official Formula One Safety Car
The SLK55 AMG was used as the official FIA Formula One Safety Car during 2004 and 2005. The role helped demonstrate that the compact roadster’s performance was taken seriously inside Mercedes-AMG, and it placed the car in front of a global audience at the beginning of the R171’s life.
7. Its styling was restrained beside its mechanical specification
Deeper bumpers, AMG wheels, larger brakes and four exhaust outlets distinguished the 55, but the body was not dramatically widened. With the badges removed, many people would see only a smart SLK. That contrast between compact roadster proportions and a hand-assembled V8 is central to the car’s character.
8. The first-ever Black Series was an SLK
Mercedes-AMG introduced the Black Series name in 2006 with the SLK55. Long before the badge appeared on SLS, GT and C-Class models, this compact two-seater established the idea of a rarer, lighter and more track-focused AMG derivative.
9. The Black Series sacrificed the folding roof
The SLK55 Black Series replaced the retractable roof with a fixed carbon-fibre hardtop. Carbon front wings, distinctive side vents, forged 19-inch wheels and a revised front bumper pushed the car further from the regular roadster. Output rose to 294kW—400PS—with 520Nm.
10. The Black Series inverted the original SLK idea
SLK originally stood for a compact, light and short roadster concept, and the folding roof was its defining feature. The Black Series removed that roof mechanism to gain rigidity and reduce weight. AMG effectively transformed a lifestyle roadster into a fixed-roof performance coupé—while leaving “SLK” on the boot.
The R171 SLK55 is memorable even before the Black Series enters the story. Add the Formula One role and the birth of AMG’s most extreme sub-brand, and it becomes one of the richest “10 Things” subjects in the Mercedes catalogue.
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Continue the story: Read our complete Mercedes-Benz SLK 55 AMG R171 history and buying guide.
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