I just removed the restrictor from my air box. I only took the top piece off for now. Am I supposed to take off the bottom piece that snaps in? Also I keep hearing people say take something off the fender. Dumb question but are they talking about the rubber thing that attaches to the drivers side-wall of the car, directly off the air box, leaving a hole in the air box? Just want to make sure so I don’t screw something up.