I have a 2002 E53 and I did upgrade the standard equipment on this car:Install.kit, Park Distance Control

http://bmwfans.info/parts/catalog/E5...tance_control/

First check the car's original wiring installation PDC preparation. My car has all the cables, so it's only about 2-3 hours labor to install PDC.
Front cables to the sensors was fixed under the headlamps and rear was folded near to the spare wheel. The PDC module is included in that kit.

NOTE: After installation, you must program modules (say the car to know that PDC is added)