yes, I did it in my e39. One thing that was helpful is that I bought off ebay for cheap a 12 inch section of the cluster wiring for the e38/9/53 high cluster. the easiest way to install it is to get the wiring and match the wire colors to the car, most of them, I would say 90 percent matched, atleast in my car. You will have to run no more then 5-6 wires to complete the retrofit, the coolant sensor, there were a couple wires that go over to the glove box area, a couple grounds, and then there were some that go to the DS footwell area buzzer. That is how I eventually installed it in my car. Before that I attempted to build a complete retrofit harness, like BMW once offered. I found all of the pins and connections through Digikey and Mouser online, except the connectors that the existing car gauge harness would plug into, that was the hardest thing, I found something that would work but it made it big and bulky so thats why I just went with the cut and solder method with the pigtail. Somewhere over on Bimmerforums I made a post with pictures and all of the part numbers involved. There is a detailed harness diagram that came from BMW that helps you with the whole thing. My suggestion would be to find that and go from there, its relatively easy from there. If I can find my old drawings I will try to post. Also, I had probably less then $40 in materials for everything involved in making the retrofit harness, but again, in the end the pigtail was easiest.