What is this Part??

[The1996BMW]

First, thanks to whoever is the owner of this pic that i used. Your car is very clean. I have two questions. Will someone please enlighten me on what the part pointed with the blue arrow is?
What is the part that holds the the floor carpeting called? THe part that holds the carpet flat on the edge by the door? Some sort of trim... thanks.

[LuvMy328is]

That is the SAP, secondary air pump. It forces air in to the exhaust mani to bring the temp of the cats up quicker. It helps lower emissions on cold starts.
~Phil

[joedapro]

thats clearly the whatchamadiggle. read your owners manual.