17x9.5?
i believe the following offsets are accurate, but since i am not positive, just use it for playing with the offset calc.
C6
Fronts - 18 x 8.5 +56mm offset
Rears - 19 x 10 +79mm offset
C6 Z06
front: 18 inch x 9.5 inch, +40 offset
rear: 19 inch x 12 inch, +59 offset
GS is the same as the Z06
Front Wheels: 18” x 9.5” (offset +40mm)
Rear Wheels: 19” x 12” (offset +59mm)
put info into the calc 'current wheel specs', then tweek the 'new wheel specs' , pressing calculate, to see new spacing.
http://www.1010tires.com/WheelOffsetCalculator.asp








