One of the most difficult problems Carlsson has is getting products to market quickly enough. A typical customer rarely keeps his Mercedes more than two or three years before buying a new model. So the engineers generally concentrate on one project at a time in excruciating detail. Case in point: during my visit the engine management wizards (tucked under a shed dormer supported by 300-year-old hand-hewn timbers) were looking for more power in Mercedes' new diesel engines. Diesels respond well to changes in injection timing but, afraid the piezo-electric crystal that controls the injectors might overheat, they built in two rest periods of 10 and 60 milliseconds during the extra 300 milliseconds the injector remains open. Now that's attention to detail.
Then there is the pressure to maintain near-stock reliability. These are new Mercedes, after all, not a turbocharged 1995 Jetta VR6 looking for a 500-hp dyno pull before the engine lets go. It takes between three and six months to develop a program with a full guarantee, according to the electronics department's Matthias Locher: "It has to be safe. We think it is better to have power that lasts." Not only that, but by using OE ECU connectors to plug between the wiring harness and ECU and piggy-back programming rather than permanently altering the board, the electronic changes are invisible to factory service computers. And the hardware can move to another car with no modifications.
Though most installations are performed through a well-supported dealer network, Carlsson still converts about 200 cars a year at Gut Wiesenhof, especially more extreme cars and trickier supercharger installations, and complete interior refits. "Anything can be realized," says marketing guru Stefan Mueller. "Though sometimes we have to say 'No' if we can't stay with our heart behind the request. Earning money is not everything." And despite the company's emphasis on individuality, a signature Carlsson look carries across the line from A-Class to S-Class: stainless steel mesh grille inserts, a new front spoiler and new rear diffuser. "Carlsson customers prefer understatement. The car looks good, but you don't know why," says Mueller.
While a Carlsson package is visually restrained, that attitude certainly doesn't carry over to performance. Spend a day in a 430-hp, CM50K (based on the ML500) doing 0-62 mph in 5.8 seconds and you'll forever wonder what the factory was thinking with its original, now boring-by-comparison specification. The supercharger conversion is unnoticeable at part throttle and moves the big rig with authority at full chat. Add some 22-inch lightweight wheels and the C-Tronic suspension lowering system and you won't be able to write a check fast enough.
Better yet, try a CK50. Even though the engineers were concentrating on new diesel engines during my visit, they had found time to work up exhaust and software upgrades good for a noticeable 40 bhp. The C-tronic lowering module (30mm max, though in nearly imperceptible steps) is smart enough to realize the Mercedes engineers programmed in a 15mm drop at speed and the Carlsson version (unlike some other programs) takes this into account while it does its magic. Just sitting behind the wheel of this mainstream flagship brings a quiet exhilaration, knowing that with the performance upgrades and a complete interior refit there is not another in the world exactly like this.
As Rolf Hartge likes to point out: "There is always a little bit more than enough.