BTW, if anyone wants to see a good explanation of what "offset" and "backspacing" for wheels means, this site gives what looks like a pretty good explanation with pictures.
https://www.autoanything.com/wheels-...el-backspacing
The reason I was looking this up is because I'm not exactly sure the rear wheels in this setup I ordered are going to clear those rear brake cooling ducts on the C5Z. If my calculations are correct concerning the backspacing of the new wheels, it appears the wheels/tires in the rear will be moved 0.75 inches closer into the wheelwell. I need to put the car up on the lift and measure what that clearance is right now with the stock wheels, but I don't think there is much clearance there at all, from what I remember. Cray's website says the wheels are compatible with the Z06, but heck, I've had "experts" work on my car before that proved to be disappointing with their "expertise". So I'm not much the trusting type any longer.