I have a 2001 X5 and purchased a Lowrance Iway-350 portable navigation unit a while back. I have always had problems with obtaining the satellite lock with this unit - sometimes in happens in a few minutes, sometimes I can't get it at all. Recently I read a discussion that this could potentially have something to do with a coating on the windshield? Is this a problem for BMWs? or is this just an issue with the Lowrance unit? I do seem to consistently (and quickly) get a satellite lock when the unit is outside the car. Has anyone had similar experiences? Do other units (Garmin, Tom-Tom, etc.) work better, or do you need an outside vs. integral antenna?