To accommodate the optional third row seat, the 2007 BMW X5's length has been extended about seven inches over the 2006 model. Furthermore, the wheelbase has grown by more than four inches, the width by more than two inches, the height by two-tenths of an inch, and the front and rear tracks by three and 2.2 inches, respectively. Curb weight has jumped up about 300 pounds. That equates to 4,982 lbs. for the 3.0si and 5,335 lbs. for the X5 4.8i.