You might want to send a message to 'lrpavlo'. He has installed lift kits without removing the struts. In order to do that, he'd have to remove the strut mount that you're referring to. The basics would be (I think):
-remove top strut nuts from above before lifting car
-put car on jackstands, struts will drop, remove wheels
-clamp springs with spring compressors (carefully!!!) just enough so that the spring isn't putting force on the upper spring seat
-remove nut that holds strut mount on
-swap strut mount
-reinstall in reverse
It may be possible to do this without clamping the spring and removing the second nut. I know that this nut can barely pass through the strut mount. In theory you should be able to drop the strut, pry the old strut mount off, put the new one on, and let the weight of the vehicle push it down over the nut. Make sure to check that the mount is seated correctly as it's pushed up into the strut tower area.
And make sure not to install the new strut mounts upside-down. (don't ask...
)
