It is always more difficult to alter the rear arches of a four-door sedan than a two-door coupe, as any work on doors can be a nightmare. Luckily, the basic C-Class shell starts off with fairly prominent rear arches that only require modifications to their edges to accommodate the wider rear track.
The largest wheels you can normally fit under the stock arches are 8.5 and 9.5x19-inch. Kicherer's in-house body specialist worked on the rebate of the rear wheel arches, reforming the metal to provide an additional 20mm of clearance. This allows enough clearance for Kicherer to use 25mm spacers with lightweight 10.0x20-inch forged alloys, wrapped in 275/25 Dunlop SportMaxx GT rubber at the rear; up front, 8.5x20-inch wheels are paired with 245/30 tires.
Thanks to bespoke ECU mapping as well as different intake and exhaust configurations in each AMG model, the 6.2-liter V8 leaves the engine plant in Affalterbach with differing outputs according to the car in which it's installed. These run from 475 hp in the C63 all the way up to 525 hp in the S, CL, and SL63 AMG models.
Regardless of output though, this in-house developed and built all-alloy motor delivers the same ear candy with its bombastic NASCAR-grade soundtrack. This is a soundtrack you want to hear over and over again, and if there's a tunnel on your daily commute, you simply never tire of rolling down a window, dropping a couple of ratios with the left paddle shifter, and nailing the loud pedal. Kicherer managed to find a few more horses with a modified airbox and free-flow filters, but bigger gains were found at the other end of the motor.
In the old days, you could always find a few extra horses by swapping out a restrictive factory exhaust. This is true to a lesser extent these days, and less so with AMG and Porsche cars, as their engineers do a very good job on the stock systems.
Kicherer goes to the expense of using bespoke tubular headers with slightly larger-than-stock pipes to extract the spent gases faster toward the 200 cell free-flow metal cats. As well as reducing backpressure, these headers, metal cats, and their stainless steel rear silencers also boost the soundtrack in richness and volume.
To maximize the effect of all this new hardware, the ECU is remapped accordingly. Since AMG uses the mapping of fuel, ignition, and variable cam phasing to throttle the output of the big V8 in its smallest car, a straightforward remap will bring peak power back up to 525 hp. From there, the gains made by the intake and exhaust mods make up the additional 40 hp claimed for the Kicherer Supersport. The final tally is 565 hp at 6800 rpm and 487 lb-ft of torque at 5200.
With the help of the limited-slip differential, zero to 62 mph is now in the four-second bracket, and with the factory electronic top speed limiter removed, you can get within striking distance of 195 mph.
The 24 percent boost in horsepower and 10 percent boost in torque are far, far more than you would normally get from a modern engine, and shows how much the factory turned down the wick on the C63 AMG. It also shows the inherent potential of the basic motor, and why the SLS AMG version is able to make 571 hp with room to spare.
Compact it may be, but the C63 AMG is no flyweight street racer. It tips the scales at 3,800 pounds, heavier than the SLS. With the extra power on tap, the stock brakes were at the limit, so Kicherer fitted their Brembo-sourced big brake kit with steel braided hoses.
The factory suspension comes in two flavors-standard with 18-inch alloys, or Performance Package with uprated springs and dampers, 19-inch wheels, and a Drexler limited-slip differential. Many owners justifiably prefer the looks of the larger wheels, but find the already-firm ride quality of the base version is tipped over the edge by the stiffer suspension. Even on supposedly smoother German roads, this is a restless combination I could not live with on a daily basis.