According to RealOEM, these are the connectors for trailer towing. Not sure which one you are looking for.
RealOEM.com - Online BMW Parts Catalog
The one on my 4.8iS is the (#3) 7 BLD RND FEM, part#61130412966
Put that part # --> www.furriousmethod.com to find vendor and price.
You also need the towing module, which ECS Tuning is selling.
Good luck!

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00 E39 DINAN S1 //M5 (82k miles)
06 E53 DINAN 4.8iS, born 2/18/2006 (126k miles) http://www.xoutpost.com/bmw-sav-foru...s-my-dslr.html
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