Only 26 units of CLK GTRs built. Intended for racing in the new FIA GT Championship series in 1997, the CLK GTR was designed primarily as a race car, with the road cars necessary in order to meet homologation standards being secondary in the car's design.
Powering the GTR was the M120 V12 based off the SL600. It displaced 6.9 liters and produced around 600bhp. Mercedes-AMG claimed 0-100 km/h (62 mph) in 3.8 seconds and a top speed of 320 km/h (199 mph). 2 of the 26 CLK GTRs were upgraded to the then new 7.3 litre AMG V12. They were called the Super Sports. Power increased to 720 bhp, offered 0-100 kph in 3.6 seconds and top speed increased to 215 mph.
Out of the 26 CLK GTRs, 20 were coupes, the other 6 were CLK GTR Roadsters.
The Guinness Book of World Records recorded the CLK GTR as the most expensive production car ever built upto 1998, with a price of US$1,547,620. (wikipedia)