I used Xd strut top mounts to lower the front a little. Partly for aesthetics, partly for maybe a smidgen more negative camber and load on the nose.
X-drive vs standard (non-sport) strut top mounts:
Xd mount is some 10mm less tall, so the car will sit ~10mm lower than with the standard mount. Note that an M-sport mount is somewhere around half way in between these 2 mounts (maybe 3mm less tall than a stock mount).
Xd bolts are a bit longer than standard ones, and need to be swapped out
L-R: Xd bolt, standard bolt, alignment pin.
The Xd bolts will foul the strut braces, being about 6mm longer than the standard bolts. I simply hammered the bolts out of my old set of standard top mounts and the Xd ones, and hammered the old bolts into the new mounts. You just need to get them in there well enough that they wont spin as you put the nut on. Tightening the nut will do the rest of the work. You should be able to get them fully home anyhow though.
Ride heights:
Measured the BMW way, but without any ballast. That is, bottom centre of wheel rim to underside of wheel arch. 18" wheels. Note that I don't have any flat ground to do this on, barring a reasonably smooth gravel driveway.
Location/Before/After Xd top mounts and M3 RSFB
FR/616/607
FL/620/608
RR/599/609
RL/596/607