Wow since your struts are around 51mm, I don't think, you'll have any problem fitting the adjustable springs. (X5M is around 65mm) If the weight of the M57 X5 is close to the F85, the springs should work fine. I'm finishing up rod bearings on the Z3M and got a few maintenance items on the X5M to do before trying out these springs.
If you need any other measurements or pics let me know.
