Fitted this along with a suite of other modifications to resolve a high CHT on #3 in our club RV9A. Was easy to install.
Will be testing the effectiveness in a fortnight if you'd like to know the results. Easy to mitigate the effects by taping over the vents between flight tests.
Highest CHT I ever saw on -14A was maybe 380, early on. Very efficient cooling with stock cowl baffles. Oil runs a little warm, but well within acceptable ranges.