Manthey may be best known for its competition Porsches – and it’s actually one of the premier builders of race cars based on Porsche products – though it also works on road-legal vehicles from Stuttgart. The latest upgrade for a street Porsche comes in the form of the Manthey Performance Kit for the current generation 911 GT3, and the results achieved are impressive.

This is much more than just an aftermarket tuning kit as it was developed in close collaboration between the Porsche engineers and the Nordschleife specialists from Manthey in Meuspath. The package is sold through the Porsche dealer network and is focused on making the car faster on track. When equipped with the kit, the 911 GT3 laps the Nurburgring in 6:55.737 minutes or exactly 4.19 seconds faster than a stock 911 GT3. Wow!

Gallery: Porsche 911 GT3 with Manthey Performance Kit

The aerodynamic tweaks are among the most recognisable. There’s a large spoiler lip at the front and additional side flaps fitted to the front fascia. The underbody of the car has been modified with new air guide elements, which increase the downforce on the front axle, a very welcomed improvement in corners. At the back, the wing gets bigger and the bumper diffuser receives extended fins made of CFRP. A very distinctive upgrade comes in the form of carbon aero discs for the rear wheels.

Porsche partnered with Manthey to develop a four-way adjustable coilover suspension that can be adapted for use on road or track. The automaker promises improved “on-the-limit handling” without sacrificing day-to-day usability. The 911 GT3 rides on 20-inch front and 21-inch rear alloys and optionally available are lightweight forged wheels, which reduce the unsprung mass by 7.3 kilograms (16 pounds). The massive wheels hide special racing brake pads, which also come as an extra-cost option. 

Porsche and Manthey tested the modified 911 GT3 on the Nurburgring with Porsche test driver Kevin Estre at the wheel. As mentioned above, the car lapped the 20.6-kilometre (12.8-mile) course of the most demanding track in the world 4.19 seconds faster than a stock 911 GT3. The track-tested kit is now available for customers around Europe with delivery planned to commence this fall. Porsche promises other markets will follow.