In 2000, development on mid-cycle updates began scheduled for 2003. By late 2001, a radical design update was chosen favoring the new brand design theme. In 2002, following discontent towards the 2001 E65 design, a more conservative appearance was instead chosen and frozen for 2003 production. In July 2003, the facelifted X5 was presented for the 2004 model year at the IAA 2003 in September, with new headlights, a few new exterior colors, a new four-wheel drive system and upgraded engines. Production started at Spartanburg on 26 September. The grilles were enlarged, as well as their actual slats being modified in a 'flame surfaced' style. In keeping with the E39 facelift of 2001, the 2004 X5's headlights got corona rings around all four headlamp projectors. The tail-lights also received a facelift similar to the BMW E39, and the exterior glass went from a "dotted" pattern to a cleaner "line" pattern. BMW invented a new four-wheel drive system dubbed xDrive shared both in the X5 and X3 in 2004. Instead of using the previous X5 system which consisted of power being split 62-38 (rear wheels-front wheels) and DSC to brake wheels without losing traction, xDrive could vary power to the front or rear axles in milliseconds, transferring up to 100% of engine power to either axle, thus allowing the vehicle to regain traction quickly. The X5 got the new 4.4i engine which debuted in the 2002 7 Series; power output rose from . Also from April onwards, a new X5 4.8is was offered (see below), producing . Sales began in September 2003. Several new extras were added to the 2004 X5 such as: Soft-boot close feature (the top part of the trunk pulls itself closed) Trailer Stability Program (making it an ideal tow vehicle) Adaptive Headlights (available only with xenon HID headlamps; these swivel with the direction of travel of the car. Bi-Xenon headlights for both low and high beam replaced the low beam HID headlights) Originally announced in the end of 2003 along with the rest of the X5 facelift, the X5 4.8is first started shipping in April 2004. It had a new larger 4.8 L engine (which replaced the 4.6 L engine), and was also later used in the 2005 750i/Li. It also included a slightly modified bodykit (parts of the bottom bumper became painted the body color), 20" wheels, and along with the 4.6is, were the only X5's