The world of modified Porsches is a big one, but few do it better than RUF. The Porsche specialist tuner and builder started out life more than 80 years ago as an independent Porsche workshop but shot to fame in the 1980s when it delivered the untamable CTR Yellowbird, a turbocharged monster based on the Porsche 911.

Since then RUF has remained active in the world of Porsche supercars, and its cars are still selling for record prices. RM Sotheby's recently listed one of RUF's more extreme offerings: the 2009 RUF CTR3. Based on the humble Porsche Cayman, this exotic car was inspired by the legendary Carrera GT and has enough power to embarrass modern supercars.

The RUF CTR3 has a unique story. Its platform was developed in conjunction with Canadian supplier Multimatic, the same company responsible for the production of Ford's Le Mans GT racer. The CTR3 has a longer wheelbase than a standard 911 to accommodate the rear-mid-mounted engine, and the exterior looks more Carrera GT and 918 Spyder than anything else.

Under the hood lies a 3.8-liter flat-six with a pair of KKK turbochargers strapped on. Total power output is a serious 682 horsepower, which is sent to the rear wheels via a six-speed sequential manual transaxle transmission. The suspension setup features a RUF-engineered multi-link rear suspension system, while bringing the 3,000-lb car to a stop is a set of 380-millimeter carbon-ceramic disc brakes.

The interior features leather-wrapped carbon fiber seats, a three-spoke steering wheel, Stone Grey carpets, Grey Alcantara trim, a six-disc CD changer, a TPMS interface, and an extended navigation module. There are estimated to be just 31 of these cars in existence, and this specific example shows only 1,700 miles on the odometer. In the exclusive world of RUF cars, this is one of the rarest, and RM Sotheby's is offering it for sale as part of its Open Roads auction running from November 11-20.