Following the collapse of the Deutsche Tourenwagen Meisterschaft at the end of 1996, Mercedes-Benz looked to the newly FIA-sanctioned GT Championship as its next major programme. The McLaren F1 GTR had dominated the predecessor BPR Global GT Series, with Porsche responding by building the 911 GT1 as a purpose-built homologation special. AMG was tasked by Mercedes with creating an equivalent car — a near-purebred racer sharing only headlights, taillights, and grille with the road-going Mercedes-Benz CLK.
To compress the development timeline, AMG purchased McLaren F1 GTR chassis number 11R from Larbre Compétition, fitting it with AMG bodywork and a Mercedes V12 engine to use as a test mule. The mule was later restored to original specification and auctioned in Monaco in 2000.
The CLK GTR's chassis was a carbon-fibre monocoque mated to an aluminium honeycomb frame, built by Lola Composites. The engine — derived from the M120 V12 found in the road-going R129 SL-Class and W140 S-Class — was extensively modified for racing use, with titanium connecting rods and a raised compression ratio of 12.0:1. Power was quoted at 441 kW (600 PS) at 7,000 rpm with 700 Nm of torque, giving a top speed of 330 km/h. The engine was mounted amidships as a semi-stressed member, with drive sent to the rear wheels through a 6-speed sequential manual transmission. Driver aids including traction control, ABS, and active suspension were banned; fore-and-aft brake bias was the only permitted aid. Front and rear suspension were identical, consisting of double wishbones with pull-rod-actuated coil springs.
The CLK GTR debuted at Mercedes' home circuit, the Hockenheimring, at the 1997 FIA GT Hockenheim 4 Hours. Bernd Schneider set pole and fastest lap but retired with brake problems, and the sister car finished 27th. Development over the summer break transformed the car's competitiveness. From the Nürburgring round onwards Mercedes began scoring 1-2 finishes; by season's end, wins at Sebring and Laguna Seca secured the constructors' and drivers' championships — with Schneider taking the drivers' title — in the team's maiden FIA GT season.
Mercedes and AMG understood the V12 was better suited to the four-hour sprint format of the FIA GT Championship than to the 24 Hours of Le Mans, so the team opted out of that race in 1997 and instead developed a bespoke Le Mans variant, the CLK LM, for 1998.
To meet GT1 homologation rules, Mercedes was required to produce a road-legal version. Only one was completed in 1997 and shown at that year's Frankfurt Motor Show; the remaining cars were built at AMG's Affalterbach facility in 1998 with production ceasing in mid-1999.
The road car — marketed with the suffix "Straßenversion" (German for "street version") — retained many racing components including the suspension geometry, sequential transmission, and carbon-fibre monocoque. Its engine was bored to 6,898 cc by Ilmor, raising output to 622 hp at 6,500 rpm and 731 Nm of torque. The 0-100 km/h time was 3.8 seconds with a claimed top speed of over 320 km/h.
Of the 28 cars produced, two were prototypes, 20 were coupés, and six were roadsters, with two coupés built in "SuperSport" specification. Two cars — one coupé, one roadster — were built in right-hand drive for Sultan Hassanal Bolkiah of Brunei. The SuperSport cars used a larger 7,291 cc engine also found in the Pagani Zonda, producing 664 PS.
At the time of manufacture, Guinness World Records named the CLK Straßenversion the world's most expensive production car, retailing at US$1,547,620. That record stood until the introduction of the Ferrari FXX-K in 2015.