Stage 4 Engine Software is for use with the High Flow Intake/Strut Brace, ensuring optimum performance and drivability. Get the most out of your performance upgrades from the combination of the Performance Software and your Dinan parts upgrades. Software upgrades are specifically designed and tuned for the Dinan upgrade. This tuning is especially noticeable in the first two gears, now catapulting the car off the line. Tuned for a smooth power-band to put down predictable and even power in all gears and throttle positions. This smoothness improves the quality of the shifting and the overall drivability. From a standing start (with the traction control fully disengaged) all it takes is the press of the throttle to the floor to get the tires spinning. The everyday practicality of a full-size sedan with the fun of a sports car, this is the definition of "Performance Without Sacrifice". With Dinan's software, your 550i will be capable of achieving its natural top speed as the governor has been removed. And as always, Dinan matches the new car warranty coverage for up to 4 years or 50,000 miles, including the possibility of consequential damages. No one offers better performance or backs it up with such comprehensive warranty coverage.