X3 xDrive35d with 3.0-liter turbocharged straight-six diesel is capable of delivering 309hp (313PS) at 4,400 rpm and a maximum torque of 630Nm (465 lb-ft) from 1,500 to 2,500 rpm, allowing for a zero to 100km/h sprint time of 5.8 seconds.
Hartge power kit boosts output to 357hp (362PS) at 4,400 rpm and peak torque to 730Nm (538 lb-ft) delivered at 1,800 rpm.
The 357-horsepower X3 can go from 80 to 180km/h(112 mph) in 14.22 seconds and from zero to 200km/h(124 mph) in 22.75 seconds, improving the regular model's times by 4.03 and 6.15 seconds respectively.
Source:
http://www.hartge.de/e/bmw_motor_6298.html