Porsche Exclusive has gone and one-upped the original designers of the 991 Porsche 911 Turbo and Turbo S. A new aerodynamics kit announced today manages to add significant downforce without increasing the car’s stock coefficient of drag.

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That considerable feat is accomplished with a front spoiler with winglets, redesigned deck lid, fixed rear spoiler with winglets (in addition to the automatically adjusting rear wing that comes on the car), and a revised rear fascia.

Tuned on the test track at the company’s development center in Weissach as well as in the wind tunnel, the aero kit manages to increase downforce at 186 mph by 37 pounds on the front axle for a total of 57 pounds of downforce, and by 40 pounds on the rear axle for a new of 331 pounds of downforce. The result extra grip should improve high-speed stability and handling.

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Available in either the car’s body color or in gloss black, the Porsche Exclusive aerokit can be ordered with a new 911 Turbo or Turbo S ($6,950), or can be retrofitted to existing cars by Porsche Tequipment ($6,886, excluding paint, assembly, and installation).

Porsche Exclusive Aerokit for 991 Porsche 911 Turbo and Turbo S

Porsche Exclusive Aerokit for 991 Porsche 911 Turbo and Turbo S

Porsche Exclusive Aerokit for 991 Porsche 911 Turbo and Turbo S

Porsche Exclusive Aerokit for 991 Porsche 911 Turbo and Turbo S

Porsche Exclusive Aerokit for 991 Porsche 911 Turbo and Turbo S

Porsche Exclusive Aerokit for 991 Porsche 911 Turbo and Turbo S