I am posting this for future considerations. I installed the Vizualogic 7" A1000 (built in DVD) system over the weekend. It was easy to install and the quality was good. The wireless FM modulation really stinks. It has this annoying humming sound when played through the speakers.
I ordered this
http://www.discountcarstereo.com/detail.aspx?ID=617 interface to see if that helps the situation. I'll post the results in this thread. Has anyone already tried this? It claims it will work with the NAV unit and factory XM.