Repro Interior Vent Grills

I need to replace my vent grills, and I was wondering what people thought of the ones listed below. I am hesitant because they are made of plastic and I want to get something quality. Does anyone know of a place that sells metal ones like the original? Anyone ever use the plastic ones and have any feedback? Thanks.

http://www.virginiaclassicmustang.com/catalog/shop/item.asp?itemid=in6793

Jon