The R170 Mercedes SLK gained a reputation as a car for young girls and hairdressers. Its automatic gearbox and the popularity of the low-powered 2.0-liter model with, well, girls and hairdressers meant it was never going to be considered a serious sporting titan. This one is rather different, however; it's a 400-bhp fire-breathing racecar that can hit close to 200 mph in a straight line.

It belongs to Carlsson, the German firm that has been tuning three-pointed stars since the early 1980s. The directors are racers at heart, and have taken to the track for several reasons--not the least of which is development. Carlsson uses endurance racing to put mileage on new parts to qualify them for the TUV certificate, which is required to market any part in Germany. Now that really is a return from the racing budget.

The components include one of the most delicious engines imaginable, a tuned version of the supercharged AMG 3.2-liter V6 that provided a much-needed shot of testosterone for the SLK range in 2001. With 331 lb-ft of torque and 348 bhp, this was a monstrous engine that took a valiant shot at reshaping the public perception of the effeminate SLK all on its own.

But Carlsson had to do a little more, setting its sights on the all-important 400-bhp mark and achieving the goal by remapping the ECU, increasing boost and adding a sport exhaust. The end result is inevitably spectacular, a unit boasting an epic 383 lb-ft of torque capable of catapulting this machine to 60 mph in approximately 4.4 seconds.

To sample the noise, try sharing a sewer with an industrial drill and a heavy metal band, and you'll be in the same ballpark. Obviously the car is stripped out, leaving a bare metal interior that refuses to soak up noise and bounces it back at your eardrums. And it's not just the noise that makes an impact, as the heat is close to unbearable. Blazing sunshine contributed, but the heat soak in the cockpit is incredible and touching the wrong place on the transmission tunnel could remove skin. After one six-lap stint I emerged sweating like a heart attack victim to guzzle water with a newfound respect for the drivers who stay behind the wheel for hours at a time.

Its pulling power keeps on going right through the range up to its 6400-rpm maximum. It's got a relatively low redline, but the low-range torque makes up for any lack of revs, and the visceral power from an engine of this size is phenomenal. It's very easy to feel like a wayward passenger on a runaway horse, struggling to keep hold of the reins.

In a straight line it's all about watching the gear shift light, pressing the heavy clutch and shoving the stick into the next slot. Carlsson went for one of the best in the transmission department, a Getrag six-speed with proven reliability in street cars that frequently handles even more horsepower for many more miles than even a 24-hour race can offer.

Downshifting was a trickier matter. Just before stepping into the car I was informed by company boss Rolf Hartge how his car was eliminated from the 2003 Nrburgring 24 Hours when its hard-charging Japanese driver revved the engine to 7800 rpm on the changedown and sent the pistons slamming into their rings. Since this is a street car engine, it cannot handle such savage treatment and blowing it sky-high is alarmingly easy to do.

"You can use engine braking on the downshift, but not too much," Hartge said, but I preferred to err on the side of caution. It cost time and must have weighed on the racers' minds, but this car was still capable of lapping with the works BMWs at Spa and should have put on a good show in the Nrburgring 24 Hours--one of Germany's most impressive touring car races and a major marketing opportunity for Carlsson.

It was gutting to watch the engine go up in smoke as Carlsson had only just upgraded the car to International A specification after winning numerous races in the 2-liter classes and finishing in the top 10 against much more powerful cars in the major races. He even made the most of the "girl's car" tag and entered a team of crack female racing drivers in the 1999 Nrburgring 24 Hours, winning the class and finishing seventh overall.

Even without help from the engine, braking was pretty savage and I was left with a sizeable bruise from slamming against the six-point harness before the hairpin on each and every lap on the test track in Metz, France. The SLK uses a brake kit that can go directly on a street car, with four-piston calipers gripping 13.8-inch discs at the front and 11-inch units in the back.

The car weighs 2,970 pounds, 300 pounds lighter than AMG's SLK, but that's just half the story as this car is significantly lighter than that without the added ballast to take it up to the minimum weight for the Nrburgring 24 Hours. By placing the weight low in the chassis floor, Carlsson has produced a machine so sharp it absolutely carves through corners.

It also refused to be unsettled by bumps in the road--an invaluable quality at the old 'Ring. Soft suspension helped its cause, although soft should be taken as a relative term. This SLK uses the same Bilstein shock absorbers with nine levels of adjustment that can be found on the company's C-Class conversion, although most road users probably wouldn't adopt the same settings for general use.

So there was some wallow, but only in the slowest corners when I went in too hot. You can forgive an inside front wheel lifting up, causing a brief moment of understeer followed by snap oversteer, when you've just taken a hairpin in third gear at more than 80 mph.

Around the rest of the circuit the car was unshakable, inspiring massive confidence in the faster corners and seemingly refusing to give up the battle for grip. Of course, the slick Dunlop tires wrapping 18-inch wheels can take some of the credit for the car's poise, but not all of it.

The SLK danced through a tight chicane that almost brought the E-Class I tested the same day to a stop in fourth gear, with just a slight confidence lift. The car simply stuck to the concrete surface and refused to let the back end slide out at all, and if the drivers knew the worst that could happen was gentle understeer, rather than a violent spin, it would certainly have inspired them to press on throughout an endurance race.

This is the key to Carlsson's racing success: The car is fast and easy to drive. It's all well and good having a super-fast machine, but if it's nervous at the limit, then tired drivers will struggle to exploit the potential pace and possibly even crash it. There were no such concerns with this SLK, which never threatened to spin, stall or step outside the realm of perfect etiquette during our time together. With some protection for the engine on the downshifts it would be the easier to drive than many, many road cars.

It's a racecar yes, but it's still a Carlsson Mercedes and that means even a hairdresser could drive it--although Hartge is unlikely to employ a team of those for next year's race.

Longitudinal front engine, rear-wheel drive

3.2-liter V6, dual overhead cams,three valves per cylinder, superchargedMods:Carlsson ECU, exhaust

Six-speed Getrag manual

Mods: Carlsson/Eibach springs,Bilstein dampers

Mods:Carlsson four-piston calipers,13.8-inch rotors (f), 11.8-inch rotors (r)

Wheels and TiresCarlsson, 9x18 inchDunlop racing slicks

Carlsson front splitter, side skirts,rear diffuser and wing

Peak Power:400 bhp
Peak Torque:383 lb-ft
Top Speed: 200 mph (est.)

Carlsson NA
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