I just did this on 2 of my kfls, and i like it. I noticed some improvements. Airflow seems ever so slightly better (because I used to screw in the afc screws just a little bit so it wouldnt back out, and now its completely open) and the whistling has improved (but not completely gone away). I also recommend taking the afc screws out.
Oh, and my vaporshark rdna finally arrived (although it didnt update at ALL until it was delivered, AND it said it was delivered at 1130 so I went to check at 130 and it wasnt there but it finally showed up at 4, stupid usps). The button is still not level, meaning it sits higher on one side than the other, but the button staying on issue seems to be gone, we shall see if it stays that way.