This cold air intake from Racing Dynamics fits the E39 BMW 540i 1997-2003 with aluminum intake tube. This intake system uses a special mandrel bent 89 mm diameter tube with a CNC machined boss welded on it to place the air filter in cold air stream. The special boss is provided for those models with an air temperature sensor. A threaded plug is included to seal off the boss for those models without an air temperature sensor. This intake works with HID headlamps. This E39 Racing Dynamics intake includes a high flow air filter, intake tube, connection hose, mounting hardware, bracket and installation instructions.