I have just installed my new cushions and I'm so excited!
Installation was a BREEZE. Be careful when detaching the old cushions because you may scratch the headset paint with the knife. I almost did that.
Insert the knife very carefully, the more "length" you slide in, the easier and gentler it'll be to pop up the cushion. Inserting just the tip of the knife requires more force/pressure to lift the cushion and unglue it, and this is how you'll scratch the sides of your headset.
Make sure you remove the "metal" piece (in my pics it's the black ring on the old cushions). Otherwise your new cushions will not be placed properly and will look separated from the headset (thanks to another review I was aware of this!).
Remove ALL the glue that's there. If it's still sticky, it needs to be cleaned. The alcohol wipe wasn't enough for removing it, but it definitely helped with the small pieces of glue. For the big ones like on one of the photos, simply lift one end of the glue strip and peel it all off at once (knife helps to lift the ends of the glue!).
Wipe it off again. Attaching the cushions is easy! Right side is different than the left; it has an indentation where you insert the cable into the headset - pretty easy to see it. There are pins on the headset, they'll go into the holes on the cushions. Play with it a bit before doing it for real, so you make sure which holes are the correct ones (not all will be used).
GENTLY lift the sticker backing with the tip of a knife (very gently... I almost ruined it!) and align the pins with the holes, put pressure all around and voilà! It's REALLY easy. The instructions are very clear.
It looks really good! I don't know how long it'll last, but I will update that whenever I know.