I have never seen Subaru approve of any such product. Even their most recent Eyesight Owners Manuals for their most recent model years say to not use any coating on the windshield. I would write Subaru of America directly and ask them. I believe you will find that your dealer is... mistaken.The dealer claims that there’s a Subaru approved aftermarket product call Diamond Fusion that is supposed to strengthen the glass and help prevent damage . . . Is anybody familiar with his product?