2004 Mercedes-Benz SLK 55 AMG (R171) 5.4L V8 7AT (360 HP)

Vehicle Overview

Unveiled just a few months after the regular model, the 2005 Mercedes-Benz SLK 55 AMG (R171) was the first of its kind. Its choice of powertrain also made it a unique proposition in its segment. No other small premium roadster with more than six cylinders was available, so it was quite a feat for AMG engineers to shove a big V8 under that sculpted hood.

Combining the open-air thrills of a compact roadster with the aggressive performance of a V8 made it truly stand out among its competitors, such as the lesser-powered BMW Z4 E85, Porsche Boxster 987, or Audi TT 8N. All of the SLK’s direct rivals were powered by four- and six-cylinder engines at the time, which also resulted in the first SLK 55 AMG being the most powerful model in its segment as well.

Another unique selling point of the R171 SLK was its retractable hardtop, which made its two-seat interior as insulated and as secure as a real coupe, with the benefit of becoming an open-top model at the push of a button. Known as the ‘Vario roof,’ the retractable top had been introduced on the first-generation SLK, and it was improved in several ways on the second generation.

Thanks to a rotating rear window, the folding roof would occupy less space in the trunk, resulting in 63 liters (2.2 cu-ft) more luggage storage volume when the roof was down. It could also be raised or lowered in just 22 seconds, three seconds quicker than its predecessor.

That said, the biggest upgrade compared to the first-generation SLK in AMG spec was arguably the powertrain. No longer a supercharged V6 but a naturally aspirated V8, the new engine completely transformed the model into a modern iteration of the AC Cobra: compact dimensions, lightweight, long hood, and a big V8 with lots of power.

The 5.4-liter V8 delivered 360 PS (355 HP) and a punchy 510 Nm (376 lb-ft) of torque, more than any other compact roadster out there. All that oomph was sent to the rear wheels through a 7-speed automatic transmission with software upgrades by AMG engineers for quicker shifting. Those numbers translated into a 0 to 100 kph (62 mph) acceleration time of 4.3 seconds, while top speed was electronically limited to 250 kph (155 mph).

The 55 AMG version retained the modern but elegant lines of the standard SLK roadster, but the extra performance demanded a more aggressive look. The front end featured a more prominent bumper with the traditional AMG A-shaped lower apron with larger air intakes for improved cooling, with the model also having a wider stance, aerodynamic side skirts, and larger 18-inch alloy wheels. Its rear end had a modified bumper that housed four exhaust tips – the SLK 55 AMG (R171) was one of the first production AMG models to feature them.