I would love this info also, my xact plug and play that I picked up in July has already fried it's antenna (which cust serv says happens often...WHAT??? ) and I need to return or exchange it. If there is a kit that works direct instead of thru FM I'll return this one and go with the kit (unless it really is $400 yikes! ) I do have the nav system and mine is a 2006.
Thanks for any help!

I can tell it's a girl 'cause she tells me where to turn.