Thanks for you advise, we will try to intsall P2 first if we can, there are a few advantange of P2.

1. with P2 installed in X5, it can tow other tailers without any additional work.
2. Wireless will require to drill hole on the trialer frame to mount, which may compromise the strengh
3. Wireless has quite footprint.
4. Since we already have P2, it's duplicate investment to get Wireless

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2012 X5 35i: Hitch installed; Coded;