The lenses are plastic. As to the quality of plastic, time will tell. I presume one could put on some OEM glass if they wanted to. My OEM glass was cracked so I wasnt in a rush to put them on.
Note that the plastic issue, may not be real. Good plastic lasts 80k no problem. BMW headlights for instance, use BOSCH plastic lens. I've replaced them on my BMW, at about 80k because they were cheap enough to not warrent polishing. Besides, polishing glass is a lot harder than plastic.
my truck
my TMI build of these headlights
http://www.toyota-4runner.org/3rd-ge...ml#post1687262
http://www.toyota-4runner.org/3rd-ge...ml#post1695815