The e92 aero lip is definitely, 100%, I am totally positive, a lip. It fits over the OEM bumper - it attaches on the underside of the car via five hex nuts which are already on your car, and on the top side of the lip via adhesive. I've installed 4 of them now, it's a lip. Oh, and fwiw, the install is a 15 minute job. Literally.
The intake sizes do not change as you suggested, maybe it is the picture.