According to British car magazine "CAR" Issue 490 June 2003; the face lifted X5 was spotted testing back to back with a VW Touareg at the Nurburgring. The car features a new grille and bonnet. The tweaks are designed to keep the X5 fresh until an all-new version is unveiled at 2006 Detroit Show.
I noticed that (from the pic provided) the face lifted X5 had similar "angel eyes" head lights found on the E39 5-serries. The car in the picture also had the rubber extensions on the wheel arches, and the 20' wheels of the 4.6 X5. BMW might have been testing the new top of the line X5. However the article did not mention that!