The last time I checked, the needle had just nudged past 174 mph, its progress slowed slightly as the car fought its way through a wall of air that was becoming ever more resistant. Even so, the Vaeth-tuned 6.2-liter in the C63 wasn’t letting up. It stayed angry, insistent and more than willing to prove that its v-max was 200 mph. As the speed climbed, the extra downforce from the front and rear spoilers made it feel as though the screws were being tightened and the car was being pressed further into the tarmac. Traffic is sparse on this stretch of no-limit autobahn just outside of Hosbach, Germany, and the wide-open left lane was every speed freak’s wet dream.
When you pass a car that’s going 100 mph slower in the lane next to you, it doesn’t look like it’s standing still. It looks like it’s in Reverse and the driver has the pedal nailed to the floor. They flash by with a quick whoosh just a few feet away. It’s unsettling if you think about what would happen if they dropped into your lane with 100 mph between the two of you, but most of your attention is focused on the road in front of you, or what you can see of it, because, for the most part, much of the road is a blur.
Sitting in the front passenger seat that afternoon was Wolfgang Vaeth (Väth in German), the founder of the tuning firm that bears his name. Before I sat down behind the wheel, he told me he was “a bad passenger,” which I interpreted as, “I hope you don’t suck at driving, because you might give me a heart attack.” Normally a charismatic, old-school tuner with strong opinions and impeccable comedic timing, Wolfgang Vaeth sat in nervous silence as I guided the C63-based, low-flying missile his company created.
When Wolfgang Vaeth gives you a tour through the Vaeth facilities, it’s akin to a history lesson. The shop is still based out of an old flour mill in Hosbach that he opened back in 1977. As you walk through the various departments, Vaeth will point out the old, reliable and seemingly indestructible machines he still uses to balance crankshafts, bore cylinder blocks and port heads. The company is as much a restorer as it is a tuner. On my visit, Vaeth pointed out a crankshaft from a 300SL Gullwing. A few feet away sat a race-spec cylinder head for their 190 2.3-16 track car. Suffice it to say, there isn’t anything with a three-pointed star that Vaeth can’t either restore or tune.
We came up a bit short of the car’s claimed 200-mph v-max on that run because of traffic, but it didn’t matter. What mattered is how it felt on its way to the serious side of the speedometer. The car’s composure was stoic, its demeanor was all business. When you enter into the surreal realm above 150 mph, a car’s weaknesses will be exposed and magnified: too much lift, weak brakes, sloppy steering, too softly sprung or damped, a lack of top-end grunt, or, in other words, confidence killers. The Vaeth-tuned C63 displayed none of those characteristics on that high-speed run. It felt as though it could run that speed all day.
Vaeth’s top-of-the-line tuning program for the C63 is known as the V63RS. It’s a 572-hp and 502 lb-ft rework of the C63’s 6.2-liter, AMG-tuned V8. The core modifications include an ECU reprogram, a high-flow air filter, a stainless-steel exhaust system and high-flow catalytic converters. But the car I drove that day belonged to the kind of client tuners salivate over.
Not content with ordering from the menu, this car’s owner wanted something special, something stealth, something designed for a single purpose. Already an owner of a Vaeth-tuned CL65 and a SL65, both capable of 200-mph-plus, the C63 would be his “beater,” if you will, good for late-night ’bahn storming, and it could be parked on the street without much concern about door or bumper dings. It had the telltale patina of hard use: a paint-chipped and bug-stained front bumper, tarnished emblems, nicked wheel rims and a lot of kilometers on the clock.
What differentiated this C63 from the “average” Vaeth V63RS was the engine. While the V63RS engine tops out at 572 hp, the engine in this particular C63 is good for 597 hp thanks to some good old-fashioned tuning we don’t see tuners doing much of anymore. The heads were ported and polished, bigger intake and exhaust valves were installed and are activated by bigger cams and stiffer springs. The pistons are lighter and forged. Vaeth said they’re designed to produce more torque but the difference in peak torque between the standard V63RS engine and this one is only 7 lb-ft (502 vs. 509). The ECU was reprogrammed to match the increased breathing, and exhaust flows through stainless-steel, high-flow cats and a titanium system. It takes six weeks to build this particular spec of engine, and Vaeth said only five of them exist worldwide. Vaeth’s oil cooler was installed and the car also uses Vaeth’s Fuel Cooler, which lowers the temperature of the gas to increase density and make each drop more powerful.
The next step was shaving weight. Vaeth’s carbon-fiber hood is part of the V63RS package, but the client went a step further and had the rear seats taken out. Other areas have also had weight taken out; Wolfgang Vaeth claimed the car is 220 pounds lighter than stock.
The car rides on a set of Vaeth’s adjustable coilovers, and I suspect they’re set towards the firmer side of the scale because the ride was stiff, even on Germany’s smooth pavement. That hard ride around town, however, was perfectly stable at autobahn speeds, yet another example of the car’s no-compromise, single-purpose theme.
The other parts of the suspension equation are forged, three-piece 19-inch wheels and Yokohama Advan Sport tires (235/35 front, 255/30 rear). Vaeth also makes a 20-inch three-piece as well for the C-Class. There’s a limited-slip differential and the brakes are six-piston calipers that squeeze 14.9-inch discs. In the limited time I had with the car, I only got to throw it into a few on-ramps. There was some body roll and you could sense the weight of the big V8 up front, but it clung tightly to the intended line.
The big V8 sits behind Vaeth’s badgeless front grille. Beneath the grille is the company’s front spoiler, which they refined in the wind tunnel to reduce lift and feed more air into engine bay to reduce temperatures by up to 6 degrees Celsius. The rear carbon lip spoiler is extended with a rubber lip on top of it and the rear diffuser is a prototype that features aluminum fins instead of the regular carbon-fiber ones.
Laying into the throttle brings out a blood-boiling, feral shriek from the titanium exhaust, like T. rex with strep throat. The seven-speed auto ’box disposes of gears with clinical efficiency and matches revs when it comes down through the gears. The car responds instantly to steering inputs and the brake pedal is firm and the bite is tenacious. It’s all very racey and very raw, but not so much that it can’t be driven daily or used for commuting. It’s like the boy racer that went to the best finishing school.
You could say Vaeth built the C-Class that Mercedes-AMG was afraid to: a Black Series C63. And they did it by thinking outside the ECU and going inside the engine to open up the airflow the old-fashioned way. Funny what you can achieve when you combine the best of both worlds.
Väth V63RS C63 AMG
Longitudinal front engine, rear-wheel drive
6.2-liter V8, dohc, 32-valve, ported and polished heads, larger cams and valves, high-flow cats, titanium exhaust
Six-piston calipers, 14.9-inch rotors
Wheels and Tires
Vaeth 19-inch, 3-piece forged alloys,
Yokohama Advan Sport, 235/35 (f), 255/30 (r)
Vaeth carbon front spoiler, carbon rear lip spoiler, aluminum rear diffuser
Peak Power: 597 hp
Peak Torque: 509 lb-ft