The objective was ambitious: to build the best of its kind. Or, in this case, to build something AMG might have done if it wasn’t constrained by budgets, lawyers and regulations.

Starting with a 2009 M-B C63, San Diego-based Automotive Connoisseur Group (ACG) first addressed the power issue – as if this 6.2L V8 had ever been accused of lacking grunt!

They bolted on a Stage 1 Weistec supercharger system that bumped power from the stock 350whp to a faintly terrifying 500whp. Along with the blower, it also included a new Euro-spec air box and mass air-flow sensor plus headers.

Now we’ve covered Weistec-supercharged cars in the past year (EC 12/11 and 6/12), so they don’t need a long intro. But to recap, the system is based on a 2.3-liter twin-screw supercharger with an innovative Constant Mu, Delta Pressure cog-drive system that helps maintain constant friction and boost pressure.

Unfortunately, 500whp wasn’t deemed sufficient to put it on a shortlist of the best C63s in the country, so Weistec’s Stage 2+ system was employed. In this iteration, the supercharger has a smaller cog, different headers as well as ported-n-polished heads with custom-ground 40mm intake valves and 33mm exhaust. You also get a bigger fuel pump, different spark plugs and re-mapped ECU.

For this machine, ACG went a step further by swapping the stock rods and pistons for Weistec’s forged, ceramic-coated, Teflon-skirted pistons and billet steel rods – apparently these were previously used in engines built to come closer to the 1000hp mark. But in this Stage 2+ configuration, the engine cranked out 693whp and 583lb-ft of torque on a recent Dynojet run.

It took just one brief test drive after the engine upgrade to come to the conclusion that the Mercedes was in need of two things: wider rear tires and bigger brakes.

The previous 19x9" rear wheels with 265/30 tires were simply overwhelmed by the engine output, sending the traction control into apoplexy and leaving the builders wondering how to fit wider tires.

Inevitably+, the only solution was to flare the rear fenders, with the cutting and fabrication taking about one week to complete. During that time, custom side skirts were also constructed to link both ends. The result looks factory fresh, with the flares maintaining the lines of the stock front fenders. But when compared side-by-side, the stock C63 looks anorexic and thin-waisted.

With so much extra room in the rear wells, ACG could fit 20x12" wheels and 325/35 Continental ExtremeContact DW tires to finally create some traction. Up front, 245/30s were wrapped around 8.5" wide wheels.

You might have noticed that thi Mercedes-Benz wears two different HRE wheel designs. On the left side are five-spoke C95s that are exclusive to ACG and can only be obtained through them. On the right are 797RS wheels in a split-five-spoke design as a further option. We’re not fans of this approach but it allows customers to visualize the different options, while the dimensions ensure both are eye-catching at least.

Behind the giant rims is a very expensive Brembo GTR brake kit. It’s the Italian company’s top-of-the-line system, comprising six-piston front calipers with enormous 405mm (15.9") two-piece rotors. On the rear are four-piston calipers squeezing 345mm (13.6") discs. Hopefully, this expensive solution has resolved the braking deficiencies, because there can be few options left, short of a boat anchor.

Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!