Xblue, Do you mean that your vibrations are more correlated with rpm than velocity? If so, I think we have different vibration sources.
Could you devolope a little bit more: "The X1 has excessively hard suspension and apparently over time parts can vibrate out of position. This happened to us during the first week of ownership/ first 600km"
Which kind of suspension your X1 has? rims size? RoF or convententional?
Edit: I`ve seen the info regarding your car in other post.