I will be looking for something of that sort. The thickness is my ennemi. Not much room to play with.
Mine isn't on and I always wanted to get it on, but for some reason I was never able to make it fit back. The planes are for some major ducting to get the air back there.
Going to sit down and think this over. And get it solved.
BTW I installed an extension to my air dam from a jetta and that helped the stability at high speed.