i have installed the tsn in my 03 and am waunting to get the xm as well....what all do i need and how hard is it to put in?....do i have to splice into the harness going into the back of the nav unit or what?....thanks for all the info in advance!!..and if anybody has the gm part #'s for the cd changer and the xm along with how to instructions that would be much appriciated!!....
