Product review (5 stars): Easy to install if you have the tools
I put aluminum foil in the bottom of my oven.  Because the heating elements are just below, the foil bonded to the original oven bottom panel.  Requires a 1/4 socket wrench to remove and replace screws.  I was able to do it myself.  An expensive lesson for me.  There was a slight scratch in the side, but not sufficient to ask for a replacement.  After all, it's an oven bottom.