After RUF’s groundbreaking CTR—nicknamed “Yellowbird” by Car and Driver—topped 211 mph, Alois Ruf Jr.’s firm entered a new era. What sets RUF apart from its tuner contemporaries is the level of attention to detail they put into each car. So much so that the German government granted the company full manufacturer status. While Ruf’s cars may be based on Porsche 911s, they are given their own manufacturer’s serial numbers.

RUF tackled the 964-generation Porsche 911 with aplomb. With the Type 964, RUF started with a car that already had streamlined styling, a comparatively neutral coil-sprung suspension, an upsized 3.6-liter flat-six, anti-lock brakes, and available 959-derived all-wheel drive. The 964 was a massive advancement over its 911 predecessor.

Porsche did not immediately follow up on the 964 with a new 911 Turbo, so RUF filled the gap with a new model available for order that it called CR. Available in rear- and all-wheel drive, the RUF CR started life as a body-in-white 911 delivered from Porsche, but without a Porsche serial number.

Ishida Engineering, the Japanese RUF distributor with a knack for ordering unusual cars, commissioned two nearly identical left-hand-drive models finished in Satin Black—save for one major mechanical difference. One would be a CR2, with rear-wheel drive, and the other was the all-wheel-drive CR4 offered here. They were built with the obligatory RUF styling kit that included a bespoke front spoiler with inlets and vents plus an RS-type rear spoiler. Eighteen-inch versions of RUF’s signature five-spoke alloy wheels wrapped around upsized cross-drilled and ventilated brake rotors. Under the big RS spoiler sat a 290-hp version of Porsche’s 3.6-liter engine teamed to a modified version of the G64 transmission. A limited-slip rear differential muscled the power to the ground.

Inside, the RUF CR4 was fitted with the company’s own three-spoke steering wheel, sports seats up front, jump seats in the rear, an upgraded center console with a storage bin, and special RUF gauges, including an 8,000-rpm tachometer and 300-km/h speedometer. RUF’s custom touches extended beyond cosmetic and performance enhancements to a high-power audio system. So smitten with the black CR4 was Alois Ruf that he christened this car “Diablo Negro,” or “Black Devil.” He even signed the underside of its front trunk saying so.

The CR4 spent most of its life in Japan. Ishida Engineering’s owner chose to keep it in his personal collection initially and used the car sparingly before it passed through a handful of other Japanese owners, accumulating that mileage over a steady pace according to Japanese road registration records. In 2014, it was re-acquired by RUF Japan—the successor to Ishida Engineering. In 2016, Diablo Negro was imported to the U.S.

Upon completing its journey across the Pacific in 2016, the CR4 was treated to a full servicing in California. It would acquire only a handful of miles as part of a private collection before its current owner took delivery, now showing just under 92,000 km. Its only modifications from when it left RUF’s operations in Germany are an appropriate Porsche Classic in-dash navigation system and softer front struts for more comfortable driving, although the original struts are included with the car. This rare RUF CR4 shows in excellent condition with limited signs of use and includes its original manuals in English and Japanese, tool set, air compressor, and spare tire.