Porsche’s delectable Type 930 took the automotive world by storm when it was introduced in 1974 as a 1975 model. By 1978, the 911 Turbo had become more civilized, but also more powerful, than its earlier brethren. Its 3.0-liter engine had grown to 3.3 liters and acquired an air-to-air intercooler housed beneath a larger rear “whale tail.” Power had grown to a solid 265 horsepower and an impressive 291 pound-feet of torque feeding through a four-speed, limited-slip transaxle.

This handsome “triple-black” 911 Turbo is quite unusual, as its first owner ordered it through a Boulder, Colorado, dealership without an electric sunroof—a specification that saved weight while stiffening the body and providing increased headroom while wearing a helmet, all boons to on-track performance driving. The car was factory-equipped with Sport Seats—distinctively finished from the factory with green piping—and Pirelli high-performance tires, and it was trimmed with “Turbo” decals on its quarter-panels. The consignor notes that the car has no known racing history, which is unusual for such “slick top” examples.

In 1997, the car was sold to William Ross, another Boulder enthusiast, who enjoyed it for three years before selling it to a Michael Franson in 2000. In 2010, this menacing-looking 911 Turbo was purchased by Tom Degorter and three years ago it was acquired by the consignor. Now displaying fewer than 33,200 miles, believed to be original, the car shows no evidence of previous damage. All mechanical components are described as having been overhauled in 2011 while under Mr. Degorter’s custody, and all systems are said to operate properly.

While “triple-black” Turbos are among the most sought-after of their kind, those without the optional sunroof are exceptionally rare, no matter the color. This handsome example is supplied with a Porsche Production Specifications certificate, correct spare wheel and compressor, jack, tools, owner’s manual, and extensive documentation covering the last 20 years of its life.