Radiator cooling plates?
 

I've seen some pics of the Password:JDM radiator cooling plates, and had a few questions about them.

First I was just curious if it replaces any of the existing pieces under the hood or if it just lays on top of them.

The other thing I was wondering is if they really have a noticeable effect on cooling performance. Has anyone with an installed one noticed more stable temperatures or anything like this? Or do most people just get this for the looks?

I've seen there is a kevlar version and a "dry carbon" version of this piece, both from Password:JDM. Are there any other similar products out there by other manufacturers? For example I've seen ones made of sheet metal for other vehicle models.

http://i.imgur.com/TfyEm.jpg

im also interested in an aluminium one. prob too many humps and round edges for a nice metal piece.

I have the Password JDM one, it replaces the stock plastic piece completely. Also, it will cover the windshield fill cap area. No problem for me as I do not want that anymore.
I believe Zele makes on also but a bit pricer than the Password JDM one.