If, as you say, "even the slightest amount of wind makes the X5 blow from side to side making it tough to stay in my highway lane," then something is certainly wrong. While an SAV/SUV will be significantly more sensitive to the wind, what you are describing is extraordinary -- I have driven large U-Haul trucks on the highway and that does not happen to them with the "slightest amount of wind."

You should take it to your dealer ASAP and let them test drive it, as what you are describing is quite extraordinary and they should experience it.