I am looking to add a plug and play Sirius XM radio to my van. We are currently using the wireless fm connection. When we do this we still notice static and have to keep changing station to keep from this. I would like to make this hard wired so we don't have the static. I am looking at either finding a way to add a aux imput or adding fm modulator to do this. However we have the nav radio (RB1) along with rear dvd for our son. I don't want to change having the ability of using the nav and keep our son listening to movies via wireless headphone while we listen to the xm. What is the easiest way of doing this? Also I would like to know if I can add the xm to my vehicle radio instead if this is an option since the book to my vehicle says some radios have this opition.