In the 2 weeks that I've had my 2005 X5, I'll be driving down a road, but I'll notice that the NAV system map will show me on its map as driving down an adjacent or near-by road usually within 400 - 800 feet of where I actually am. This issue is a bit of a problem when using the guidance system as it will start giving incorrect instruction because it thinks I am off course on a road that I'm really not driving on. This has occurred so far only on state and county highways as opposed to major highways and interstates...but the state and county roads are where the NAV system is most useful for me. I've noticed this mostly in Upper Westchester County, NY, and Fairfield County, CT, so it's not like I'm in some uncharted rural area that wouldn't be familiar to any decent NAV system. Anyone know if it's a system error on my NAV or is this something that occasionally occurs that can be fixed with some kind of calibration? I owned a GM with NAV recently that did not have this problem in the same areas. Thanks.