BMW engineers are obviously focused on braking and acceleration, but they've also spent plenty of time on the 2007 X5's ride and handling. All versions benefit from xDrive all-wheel drive, traction control, hill descent control, and BMW's Dynamic Stability Control system (DSC-X). Hardware includes a speed-sensitive rack-and-pinion steering assembly, 18-inch alloy wheels rolling on 255/55 run-flat tires, an all-new double-wishbone front suspension, and a multi-link rear setup including coils on the 3.0si and air springs on the 4.8i with its automatic load-leveling suspension.