I have it from factory on mine (was a standalone option I went with). If you want to retro to the factory lighting, I wouldnt recommend it. MB overengineered the system, and the door panels are different dash is different. Ive had my doors off and the LED units are integrated into the revised doors...channels in there, formed LED enclosures, wood trim is different to house the strips etc. Doesnt look like just different wood trim, there are molded channels in the inside of the door to mount the strips and associated wiring. This isnt an easy upgrade. Unknown if you can tell onboard computer you have it to turn on...prob requires dealer reprogram. Problem with these cars is that the program is VIN specific, so it isnt easy to just flip options on.