For example, GM needs to re-coordinate with vendors involved in supplying various electrical components and all other related equipment. Of course, this will not affect the design inside or outside, but it is still quite a commitment this late in the development process. But the big question is how has this happened (assuming the information is accurate)? Is not this something engineers should have taken far earlier in prototype testing? What about advanced data models? Why did not they identify the problem? The answers to these questions will probably come across over time.
The C8 Corvette is still on track to be ready for the 2020 model year, but we should not rule out a 2021 launch entirely. A six-month delay is not the end of the world, but it is still disappointing.