A fair count of people have.
Sadly, its far easier to tackle with the entire bumper skin/cover off the car, given the screws that hold it in place at the far far end of the rear splash guard plastic.
You can attempt it from below by removing the rear splash guard (still need to access the hiddeb screws... not just the ones under the cover clips) and then it becomes possible to remove the stock diffuser, held in mostly by clips and those hidden screws.
The service manual outlines the removal reinstall decently well.