my dealership provide me with a VIR (vehicle Inquiry Report) when I placed my order it showed the breakdown of the the order place with BMW. And I believe the X5M actually comes with adaptive drive (dynamic sway bars)

Edit: Car_Girl it looks like you have x5 50i, from realoem it looks like 226 is not a option for the 50i but for the 35i(what I have).
50i see: RealOEM.com * BMW E70N X5 50iX Stabilizer, rear

35i see: RealOEM.com * BMW E70N X5 35iX Stabilizer, rear