I was told that if you get a "novice" handling the TPMS unit and it gets damaged in the tire/rim swaps it is more painful to troubleshoot, rather than get a wheel/rim set with it's on set of "Correct BMW X5 compatible" TPMS sensors.
After I had 3 trips to the Discount Tire and 1 to BMW dealer over two weeks (all for TPMS fault-related issues), I would say it is money well spent.