I installed the factory unit complete with trailer wiring for about $1200 CDN or$800 US complete and on the vehicle--Loking at the installation I expect my regular hitch guy( who has installed on our previous series 46 328,series 39-540i and the big current 740) could have fabricated for about $200US for a class 3 hitch--I made the mistake of ordering from BMW because I thought it would be more convenient now the were actually selling hitches in North America--to bad I didn't ask the price 1st! I dont think its worth the money get it done custom for less JP I just bought an X5 with sports pkg yesterday. Does anybody have experience with putting a trailer hitch on it? BMW factory or aftermarket? Price? I heard that factory is $1500, maybe they're putting transmission cooler on it. I'm just going to be using a bike rack and small inflatable on trailer.