Rear Air Bag Suspension Coil Spring Conversion Kit Set Driver Passenger for X5. 2007-13 BMW X5 Rear Air Bag to Coil Spring Conversion Kit. 2000-06 BMW X5 Rear Air Bag to Coil Spring Conversion Kit. 2008-14 BMW X6 Rear Air Bag to Coil Spring Conversion Kit. In the event this item should fail due to manufacturing defects during intended use, we will replace the part free of charge. This conversion kit is used to convert the factory equipped air ride suspension system with a more simple and rugged coil spring setup. Lowest price on brand new, in-the-box auto parts. In order to keep our prices low, we have the following purchasing policies. We’re here for you!