Tadge of Team Corvette :

I see the reference to both Stingray and Z06, so I will address both starting with the Stingray:

We do all of our track validation with the front plate removed and I am not aware of a case of overheating when a Z51 car is properly prepared.

The article referenced talks about cooling issues on the street when driven aggressively in hot temperatures with the front plate installed.
I see in the picture of the Edmunds long term test, the car has a front plate in what we call the "show" position and so when driven very aggressively had insufficient cooling.

As discussed in the owner's manual, this panel is "to be removed when driving aggressively or in hot weather".
All cars shipped to states that require front plates also have a plate frame that mounts higher on the bumper and does not block as much of the cooling flow.

Because states have varying height-to-ground requirements the plate holder sits high on the front bumper to accommodate those laws.
While fully legal and beneficial for cooling performance, it doesn't look very good and many customers have asked for a more integrated solution, hence the optional "show" position centered on the grille. Although intended as a "show" position, for 99% of street usage the cooling performance is fine.

Some may be quick to point out that other cars seem to be able to have low front plates and robust cooling (fourth and fifth generation Corvettes, for example), but those are "bottom breathers" with major compromises to down force performance.

Although there are very few complaints from Z51 customers on cooling issues, we are looking at taking some of the learning and hardware from the Z06 and making them available on the Stingray.

For example, the front-mounted supplemental trans cooler developed for the Z06 automatic will be included in the Z51 package for automatic coupes starting in the 2016 model year.

We have discussed the Z06 cooling robustness in this space before and are very concerned about what some customers are experiencing.
We have built over 8,000 Z06's so far with the vast majority of them having no cooling issues. We are working to gather data from customers (some of whom may have posted here) who have concerns and are in the process of sorting through that.

We have found a few build issues, a few prep issues, and some vehicle mods that have hurt cooling performance.
An example of a build issue would be an improper bleed of the intercooler circuit.
Even a small air bubble can impact performance.

As I indicated in in my last "Ask Tadge" answer, we design for 30 degrees centigrade and have for decades without customer dissatisfaction.
We may have to move our target upwards since customers appear to want to run their cars very hard at elevated temperatures.

The question asks about what kind of cooling upgrade could be made available through GM performance parts.
I can tell you we are looking at a variety of robustness improvements that could take many forms.

It could be in calibration (and for followers of these threads, we haven't forgotten about the "rough track" chassis calibration talked about a few weeks back), cooling system or specification changes, or even super charger hardware tweaks.

It will take us a while to work through what makes the most sense and to do the validation, but we will make every effort to make sure that the changes are backwards-compatible to vehicles already produced. In the meantime, we sincerely appreciate the customers we've contacted openness and willingness to work with us on continuous improvement.