There's an issue with clip-on mics, though. I've had times where the clip-on mic ends up underneath my shirt collar and it muffles my voice. Or if I move around and rub the mic against my clothing it makes a wonderful metallic sound that I'm sure you've probably heard when gaming with me. A ModMic is much more convenient to use. Plus they use a 3M adhesive which is easy to remove without residue when you go to sell the headphone eventually.
Given that there's a nice big obvious mounting plane there, I withdraw my comments. But I still hold that I wouldn't mount it to the grill of one of the most well-regarded summit-fi headphones available. When you can significantly change the sound by adding a tiny bit of fluff to the back wall of the ear cups, I wouldn't risk it...