Check out an ultra-rare Porsche 911 RSR Evo

This 26-year-old Porsche 911 started its life as a track-only Carrera RS, but was later continuously upgraded until it became an RSR Evo spec with a modified engine. The seller claims its specs make it exceptionally rare, so the current bid of $115,000 USD may be not out of place.

John Ruther, one of the chiefs of the Porsche Club of America, bought the car for himself in 1995. It was a SuperCup-spec 911 Carrera RS equipped with a 3.8-liter naturally aspirated engine. Two years later, Porsche Motorsports assisted in upgrading it to RSR Evo, including a swap to a 3.8-liter RSR Sprint engine.

According to reports, Porsche only made 45 such engines in 1997. They featured reinforced and at the same time lightweight parts (for example, some were made of titanium), different ignition and special throttle valves. The output amounted to 390 PS (385 hp / 287 kW) or so.

Ruther additionally replaced the OEM exhaust system with a spool-valve system designed by Teilert Engineering, and claims that it made the build unique. A new ECU helped increase the power to 410 PS (404 hp / 302 kW).