Some numbers in the car world bear special significance. Whether it’s or , when you start talking about them as an enthusiast, there’s usually a sense of hushed reverence. For Mercedes-Benz, this number is 6.3. This is a reference to the that Mercedes built in the 1960s, which was an all-conquering sedan that shattered speed records in unimpeachable style.

Fast forward 50 years or so, and that number has made a comeback, this time as a signifier for AMG performance models equipped with and its . This engine saw duty in the C63, E63 and S63 models, and, in my personal favorite, the CLK63 Black Series – a car I’ve always loved but never driven until Mercedes offered me an hour with one during Monterey Car Week.

Before I get into what it was like to drive, we should talk about what differentiates the Black Series from the standard CLK63. The obvious exterior differences include a little carbon trunk spoiler, 19-inch forged alloy wheels and big ol’ carbon fender flares. Inside, there are lots of carbon fiber accents, and the rear seats have been deleted. Not-so-obvious changes include AMG-tuned Black Series-specific coilovers, a re-tuned seven-speed automatic, a mechanical limited-slip diff, bigger brakes and bigger air intakes. For such an intense car, the changes now seem pretty subtle.

Starting the CLK is also a more subtle experience than I expected. Where today’s performance cars tend to start with a huge, angry bark that settles into a diesel-like idle, the CLK sort of grumbles itself into existence and then lopes along until you prod it. The M156 engine – the first developed entirely in-house by AMG – despite its size, loves to rev and makes its peak of 500 horsepower (25 more than the standard CLK63) at 6,800 rpm. There’s plenty of torque, too, with 370 lb-ft available around 2,000 rpm and a peak of 465 lb-ft at 5,250 rpm.

That expansive rev range and its naturally aspirated character mean that the Black Series is a car that likes to be worked. Revving the engine out elicits less overall noise than you’d expect from something as special and limited as this, but it’s all good sound and all real, with no tuned-in bangs or pops from the exhaust.

500 hp isn’t that much by today’s standards, but today as in 2008, it’s not the end of the world. Even when you consider that the CLK Black with its carbon fiber and rear seat delete was still tipping the scales at a positively porcine 3,920 pounds, it’s still an experience, even if it doesn’t feel as quick as something with the modern 4.0-liter Biturbo motor.

By 2008, Mercedes had long since bailed on the manual transmission as a concept, and so it shoved a seven-speed auto in the CLK. On the surface, this is a bummer, as a manual would have been more engaging and probably helped to shave some weight, but this auto is a good one – by 2008 standards. Shifts are reasonably quick, if not immediate, and it mostly shifts when you want it to, and, hey, it could be a lot worse; it could be an automated manual like BMW’s SMG transmissions.

The Black Series’ bespoke suspension setup is decent for road use. The little streets around Monterey aren’t exactly brutal and broken, but the car felt compliant enough for daily use. It’s not necessarily plush or even something I’d want to daily, but you’re not going to rattle any fillings loose. The car’s AMG-branded Brembo brakes are awesome and feel unflappable, thanks to their big six-piston calipers and two-piece rotors up front.

The early-to-mid aughts weren’t a great time for Mercedes’ interior design or quality, and despite its whopper of an as-new price tag ($138,000 in 2008 or around $197,000 in today’s money), this thing is still mostly a C-Class. The seats are nice but not overly supportive, and the materials generally suck — Europe got fixed-back bucket seats, but they weren’t legal for the US at the time. The car also definitely , which is a plus for me, someone who has owned a bunch of late-90s and early-2000s German cars, but it could be a bummer for someone else.

While the Black Series was initially envisioned as a sort of tribute to the then-contemporary F1 safety car, it made the journey to the road pretty well. My driving experience was limited, but I imagine it as a car that would happily hustle up a canyon road, provided it wasn’t too tight, and it would look epic cruising around LA with all four windows down. It’s been eclipsed by AMG cars many times over in performance terms, but it’s hard to argue that the first-generation CLK Black Series doesn’t have style to match its still-nearly-six-figure price tag if and when you find one for sale.