Does anyone know what the splash guard is called that is attached underneath the front of the car just behind the bumper, and protects the radiator and front part of the engine? Can someone give me a website where I can buy one?

I have a 2003 CTS, and mine is ripped up.

 

Hey, I just looked up a 2005 CTS in the service manual, and the large panel directly under the front of the vehicle is referred to as the "Air Deflector". This is the large piece of plastic that is held in place by approx. 14 fasteners.
My SRX has the same things.

Where to buy one is a great question, as you can do through the dealer or I'd consider even a wrecker and or Ebay (where I get a lot of misc parts).

If you would like, pm me your email address and I can shoot you over some images from the service manual to make sure that this is what you are looking at.

Cheers,
CadiKam