The factory 22" radiator mounts are shown with red arrows. The 26" upper radiator mounts are shown with blue arrows. The core support itself has these outer flanges, the 26" radiator opening is basically out where those flanges are. And I should have been more clear, it's closer to two inches
per side that the opening is different.
View attachment 1716042269
Here are some factory 26" supports...
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View attachment 1716042274
You can see that it would be a ton more work to swap the whole support vs just modifying the one that you have. As for the size of the opening, I've never had an issue keeping my car cool when it's at speed, which is when having the smaller opening would be the most impactful. If anything my car will run too cool when it's at speed, it almost always cools all the way down to whatever temp thermostat I have in the car. I have an electric fan set up on the back with a shroud that covers the entire core, so, when the fans are running they pull air across the entire core.
