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The C6.R ZR1 GT2, if you were to use its full name, was the model used in the last four years before the Corvette C7.R was introduced, and had a slick sequential manual operated by paddles that was combined with the rear differential to create a rear transaxle. This style of transaxle eventually made it into the road-going Corvette, especially the Grand Sport and ZR1 of the C7 generation.
In late 2007 Corvette Europe approached the FIA seeking approval to race a C6 Coupe in the GT4 category.  After much study the FIA approved their request.  Kroymans shipped a new 2008 C6 Z51 six-speed coupe to Callaway Competition in Leingarten, Germany. In less than six weeks the Callaway team stripped the new car of all non-essential parts including carpet and standard seats. 
Corvette GT3 C6 Z06-R
During the summer of 2005, a decision was made to transform selected Z06 road cars into a new breed of racer to compete in the world's top GT3 championships. The first series to introduce this new GT3 class was the SRO and FIA's GT3 Championship. Based on their racetrack test results, Team Carsport saw instant potential in the car. Hezemans contracted Callaway Competition in conjunction with Koos Pettinga, manager at Corvette Europe, to convert the street Z06 into a Z06R GT3.
Corvette C6R
The Corvette C6-R race car debuted at the 12 Hours of Sebring in March 2005. The two-car, factory-backed Chevrolet sports car program competed in the production-based GT1 class (formerly GTS) of American Le Mans Series as well as the legendary 24 Hours of Le Mans in France. It was the most technically advanced sports car ever developed by GM, culling years of experience from the Corvette C5-R as well as the advancements brought forth from the next-gen Corvette C6 and Z06.