Include

[No Doubt]

The C6 Z06 might end up orphaned as far as racing is concerned.

The C6-R will probably be based on the C6 coupe with its steel frame. The overall body design of the C6 coupe and C6 Z06 is outwardly similar enough that when combined with hybrid body modifications, as in the ALMS series, will not present a problem. In other words the C6-R is probably going to be a highly modified C6 coupe with its steel frame and not a Z06, although it may borrow some Z06 design features.

SCCA T1 rules do not permit the C6 Z06 but rather the C6 coupe instead. They also mandate a steel cage welded to the (steel) frame.

Another factor that needs to be considered is why would GM use a hydroformed aluminum frame rather than steel? The answer is of course weight savings. But why is that important on a production street car? The reason is the CAFE standard, or "Corporate Average Fuel Economy". Generally speaking the more a vehicle weighs the less its fuel economy and when you take the average fuel economy of all a companies vehicles combined they must meet the CAFE standard.

The Energy Policy and Conservation Act of 1975 required passenger cars and light trucks with a gross vehicle weight rating (GVWR) of 8,500 lbs. or less manufactured for sale in the United States, to meet CAFE standards. The CAFE standards are applied on a fleet-wide basis for each manufacturer; i.e., the fuel economy ratings for a manufacturer's entire line of passenger cars must average at least 27.5 mpg for the manufacturer to comply with the standard. If a manufacturer does not meet the standard, it is liable for a civil penalty of $5.00 for each 0.1 mpg its fleet falls below the standard, multiplied by the number of vehicles it produces.

Given the likelyhood the new Z06 will have around 500 horsepower it can't weigh significantly more than the C5 Z06 or its fuel economy would likely suffer. When you take into account the other added 'features' such as transmission and engine oil cooler, etc. the need to reduce weight somewhere else became of concern. Combine that with the 'marketing' potential of "500 Horsepower!" and you can see why this may have been part of their rationale.