Hi, does anyone know what is "extra" with the above option?

The truck is a 2003 with a sunroof (moon roof?) with "extress open", i dont think it has roof monitors though.

Check out this link. It's for a 05.
DK8 should be on the first page.
http://media.gm.com/division/2005_prodinfo/cadillac/esv/Escalade%20ESV.pdf

Hi, thanks, this helps alot (saved as explains other stuff)

No problem. Good luck with your search.