Rather oddly (maybe not) in the US and on the US BMW X5 Forums, one of the promoted and often talked about positively, mods is to fit big springs to the rear tailgate gas struts. The sole purpose of these being to boost to opening force of the upper tailgate, so hat it requires no manual lift to raise all the way to its top most open position. Dangerous in the extreme, I have visions of peoples teeth flying through the air and across the car park as the newly fitted springs boing into action, launching the tailgate upwards on the unwary who has never encountered this mod.
I mentioned my fear on one of the forums and was laughed out as a "snowflake"